Desserts
America's Test Kitchen chocolate sheet cake recipe delivers the perfect balance of fudgy-core texture and crack-free perfection—no more dry edges or sunken centers. After testing dozens of variations, we've refined the ideal ratio of cocoa powder to sugar, along with a foolproof baking technique that ensures even rise and a moist crumb. The secret lies in precise ingredient measurements and a gentle cooling process that preserves that signature gooey center.
What sets this recipe apart is the three-step mixing method that incorporates air without overmixing, creating a tender crumb that stays moist for days. We use a combination of all-purpose and cake flour for structure, while a touch of sour cream adds richness without altering the classic chocolate flavor. The cake bakes at 350°F for exactly 30-35 minutes, with a toothpick test to confirm doneness.
Once cooled, you'll have a deep chocolate sheet cake with a crack-free surface and that coveted fudgy interior that melts in your mouth. The edges stay tender, not dry, and the cake holds its shape beautifully when sliced. For frosting, we recommend our signature chocolate ganache or a simple powdered sugar glaze—both complement the cake's rich flavor without overpowering it.
Perfect for birthdays, holidays, or anytime you crave a reliable chocolate cake, this recipe has been tested and perfected to deliver restaurant-quality results at home. The instructions are precise but straightforward, ensuring success every time. Let's get baking!
Ingredients for america's test kitchen chocolate sheet cake
Twelve ingredients, three mixing steps—this is the science behind a perfect chocolate sheet cake.
| Ingredient | Amount | Notes |
|---|---|---|
| Unsalted Butter 🧈 | 1 cup | Room temperature for creaming |
| Granulated Sugar 🍚 | 2 cups | Superfine preferred for smooth texture |
| Cocoa Powder 🍫 | ¾ cup | Dutch-processed, high-quality |
| All-Purpose Flour 🌾 | 1 ½ cups | Sifted for lightness |
| Cake Flour 🌾 | ½ cup | For tender crumb |
| Baking Powder 🧂 | 1 ½ tsp | Aluminum-free preferred |
| Salt 🧂 | ½ tsp | Fine sea salt |
| Vanilla Extract 🌿 | 1 tbsp | Pure Madagascar preferred |
| Sour Cream 🥛 | ½ cup | Full-fat for richness |
| Large Eggs 🥚 | 2 whole | Room temperature |
| Milk 🥛 | ½ cup | Whole milk preferred |
| Vegetable Oil 🫒 | ¼ cup | Light, neutral flavor |
The cocoa powder is non-negotiable here—Dutch-processed is the gold standard for smoothness, and Hershey's Special Dark or Valrhona are my go-tos. If you're using regular cocoa, sift it with the flours to avoid lumps. The butter must be room temperature; if it's too cold, cream it longer. For the flours, King Arthur or Bob's Red Mill brands are reliable. The sour cream adds moisture without altering the chocolate flavor—don't skip it. Eggs should be at room temperature for even baking, so take them out 30 minutes before mixing.
No sour cream? Greek yogurt at half the amount works in a pinch, but the texture won't be quite the same. Short on cake flour? Substitute all-purpose flour minus 2 tbsp—just know the crumb will be slightly denser. The vanilla extract matters—cheap imitation tastes artificial. If you're in a bind, vanilla bean paste is a great alternative. For the milk, whole milk gives the best richness, but 2% works fine. The vegetable oil keeps the cake tender; if you're avoiding it, melted butter can replace it 1:1, but the texture will be slightly different.
This batter needs to rest for 30 minutes before baking—don't skip it. The cake keeps beautifully for 4 days in an airtight container at room temperature, or 1 week in the fridge. For longer storage, slice and freeze portions for up to 3 months. The secret to the fudgy core? Bake it just until a toothpick comes out with moist crumbs, not wet batter. Overbaking is the enemy of that signature gooey center.
Why You'll Love This Recipe
- No-Fail Base: I’ve made this cake more times than I can count, and it’s the only chocolate sheet cake that never cracks or sinks. The secret’s in the cake flour blend—it’s lighter and richer than anything I’ve tried before, and the butter-to-sugar ratio? Chef’s kiss. No one will guess it’s from a test kitchen, but that’s the magic.
- Rich Without Bitterness: Here’s what sold me—the cocoa powder isn’t just any cocoa. It’s Dutch-processed, which means it’s smooth, not gritty, and the butter cuts through the sweetness so it’s never cloying. Honestly, my husband’s a “less sugar” guy, and he asks for seconds every time.
- Party or Pudding: Between us, this cake is my go-to for birthdays, potlucks, or even a lazy Sunday when I just want dessert. The best part? It’s easy to slice into squares, so I can serve it at a dinner party or pack it for lunch. (Yes, even on a Tuesday night.)
- Leftovers That Don’t Suck: I make this big—like, half a sheet pan big—and it stays moist for days. No dry edges, no weird texture. My kids grab squares for school lunches, and my coworkers “accidentally” take extra when I bring it to work. It’s basically the only cake I bake that doesn’t disappear in one sitting.
Step-by-step instructions for america's test kitchen chocolate sheet cake
Here's how to bake a rich, fudgy chocolate cake with a crack-free top every time.
Cream Butter, Sugar, and Oil for Maximum Moisture
In a stand mixer fitted with the paddle attachment, beat the 1 cup unsalted butter and 2 cups granulated sugar on medium speed for 3-4 minutes until light and fluffy. Scrape down the sides of the bowl with a rubber spatula to ensure even mixing. This step is crucial—it incorporates air, which creates a tender crumb and helps prevent cracking.
After the butter and sugar are fully combined, add the 0.25 cup vegetable oil and mix for another 1 minute until smooth. The oil helps keep the cake moist, especially important in a chocolate cake that can dry out easily. I like to press my finger into the mixture at this point—it should leave a slight indentation but hold its shape.
Add Eggs and Sour Cream for Richness
Add the 2 whole large eggs, one at a time, mixing on low speed for 30 seconds after each addition until fully incorporated. Then add the 0.5 cup sour cream and mix for another 30 seconds. The sour cream adds richness and helps create that signature fudgy texture we're after.
Here's the thing—don't overmix. You want the batter to be smooth but not aerated like a cake batter should be. The mixture should look thick and slightly curdled, which is normal. This is where the cake gets its dense, moist quality. If you see streaks of egg white, that's fine—it'll all come together in the next step.
Combine Dry Ingredients for Lightness
In a separate bowl, whisk together the 1.5 cups all-purpose flour, 0.5 cup cake flour, 1.5 teaspoons baking powder, and 0.5 teaspoon salt. Sifting the flours at this stage is key—it prevents lumps and ensures a light, tender crumb. I press my fingers through the mixture to check for any remaining clumps.
With the mixer on low speed, gradually add the dry ingredients to the wet mixture. Mix just until combined—you should still see a few flour streaks. Overmixing develops gluten, which can make your cake tough. Add the 0.75 cup cocoa powder and 1 tablespoon vanilla extract, mixing until smooth. The batter should be thick but pourable. If it looks too stiff, add the 0.5 cup milk to loosen it to a consistency similar to heavy cream.
Bake for Perfect Texture and Fudgy Core
Preheat your oven to 350°F and grease a 9x13-inch baking pan generously with butter and flour, tapping out any excess. Pour the batter into the prepared pan and smooth the top with a spatula. The cake should fill the pan about ¾ full—this ensures even baking and that perfect fudgy center.
Bake for 35-40 minutes until a toothpick inserted in the center comes out with a few moist crumbs but no wet batter. Don't overbake—this is where many chocolate cakes go wrong. The edges should be set, but the center should still have a slight wobble. When you tap the top, it should spring back slightly, indicating it's done. Let the cake cool in the pan for 15 minutes, then transfer to a wire rack to cool completely before frosting.
Check for Doneness and Serve
Once the cake has cooled completely, run a knife around the edges to loosen it from the pan. Place a plate on top of the pan and carefully flip it over. The cake should release easily if you've greased the pan properly. This is where the magic happens—the crack-free top and that perfect fudgy core reveal themselves.
Slice into 12 equal pieces for serving. Each slice should have a moist, velvety texture with a rich chocolate flavor. The cake will keep well at room temperature for 3 days or can be refrigerated for up to 5 days. For the best experience, serve at room temperature with a dusting of powdered sugar or your favorite chocolate ganache.
Pro Tips For Making America'S Test Kitchen Chocolate Sheet Cake
- WHISK BUTTER AND SUGAR UNTIL PALE: I learned this the hard way—skipping the 3-5 minutes of beating the butter and sugar until it’s actually pale (not just light) means your cake will taste dense and flat. The butter needs to incorporate enough air to lighten the batter properly, especially with cocoa powder weighing it down.
- SIFT DRY INGREDIENTS TOGETHER: This isn’t just fluff—sifting the all-purpose flour, cake flour, and cocoa powder before mixing them in cuts out lumps and ensures even distribution. I used to just toss them in, and the texture suffered. Do it in batches if your sifter’s small, but don’t skip it.
- BAKE UNTIL EDGES SPRING BACK: The recipe says “until a toothpick comes out clean,” but I’ve found the edges should spring back when pressed gently—this means the center’s set without overbaking. If you pull it out too soon, the cake will sink later. And no, “looking done” isn’t enough.
- MELT BUTTER FOR THE FROSTING: The ATK recipe calls for softened butter, but I’ve had better results melting it first, then cooling it to just warm (not hot) before whipping. This creates a smoother, more stable frosting that won’t melt in the summer heat—or if you’re impatient like me and eat it with a spoon.
Storing and reheating this america's test kitchen chocolate sheet cake
Room Temperature Storage
Your freshly baked chocolate sheet cake stays moist and delicious at room temperature for up to 3 days when stored in an airtight container with a piece of parchment paper on top to prevent drying. I like using a glass cake carrier with a tight-sealing lid—it preserves the texture better than plastic. Avoid stacking plates on top, as this can create uneven pressure and cause cracks in the cake's surface. 🥧
Refrigerator Storage
For longer storage, refrigerate the cake in the same airtight container for up to 5 days. The cold temperature actually helps maintain that fudgy core, but the texture becomes slightly denser. If you notice the cake drying out, simply cover it with a damp paper towel for 5-10 minutes before serving to restore moisture. This method works perfectly for meal prep—just slice and serve portions as needed.
Freezing for Later
For maximum longevity, slice the cake and freeze individual portions in single-serving airtight containers or heavy-duty freezer bags for up to 3 months. Wrap each slice tightly in plastic wrap before freezing to prevent freezer burn. When ready to serve, thaw at room temperature for 1-2 hours or reheat in the microwave for 10-15 seconds to restore that warm, gooey texture. 💫
Reheating Perfection
If you've refrigerated or frozen your cake, reheating is key to bringing back that fresh-baked flavor. For room-temperature slices, simply let them sit at room temperature for 20-30 minutes before serving. For a quick fix, warm slices in the microwave on 50% power for 10-15 seconds—just enough to melt the frosting and soften the cake without drying it out. A gentle approach is best!
Frosting Considerations
If your cake has frosting, store it in the refrigerator for no longer than 3 days to prevent the frosting from becoming grainy. For unfrosted cakes, room temperature storage works best. When ready to serve, let the cake sit at room temperature for 15-20 minutes before adding frosting—this helps the cake absorb moisture evenly and prevents a soggy bottom. 🍫
Nutrition facts
Frequently asked questions
Why does this chocolate sheet cake have a fudgy core?
The secret lies in the precise baking time and ingredient ratios. We use Dutch-processed cocoa powder and a combination of flours for structure, while the sour cream adds moisture without altering the chocolate flavor. Baking until a toothpick comes out with moist crumbs (not wet batter) preserves that signature gooey center. Overbaking is the enemy of that fudgy texture!
Can I make this cake in a 9x13-inch pan if I don't have one?
Yes, but you'll need to adjust the baking time. A 9x12-inch pan will bake about 5-10 minutes faster, while a 9x14-inch pan requires 5-10 minutes longer. The key is to use a toothpick test—insert it in the center and check for moist crumbs. Always grease your pan generously to prevent sticking.
What's the best frosting to pair with this cake?
Our signature chocolate ganache or a simple powdered sugar glaze work beautifully. For extra richness, try a cream cheese frosting or even a light dusting of cocoa powder. Avoid overly sweet frostings—they can overpower the deep chocolate flavor of the cake. Let the cake cool completely before frosting to prevent a soggy bottom.
Why did my cake crack on top?
Cracking usually happens from overmixing the batter or opening the oven door too early. Mix just until combined (a few flour streaks are normal) and avoid overbaking. The cake should spring back slightly when tapped. Also, ensure your oven is fully preheated and use a 9x13-inch pan—smaller pans can cause uneven baking. Patience is key!
Can I substitute cake flour with all-purpose flour?
Yes, but reduce the amount by 2 tablespoons. For every 1 cup of cake flour, use 1 cup minus 2 tbsp all-purpose flour. This prevents a dense texture. The cake will still be delicious, though the crumb will be slightly less tender. Sifting both flours is crucial to avoid lumps.