Ingredients
Scale
Chocolate Sheet Cake
- 1 3/4 cups (210 g) all-purpose flour
- 1 3/4 cups (350 g) granulated sugar
- 3/4 cup (about 64 g) natural unsweetened cocoa powder
- 1 1/2 teaspoons baking soda
- 1 teaspoon baking powder
- 1/2 teaspoon fine salt
- 2 large eggs, room temperature
- 1 cup (240 ml) whole milk, room temperature
- 1/2 cup (120 ml) neutral vegetable oil
- 2 teaspoons vanilla extract
- 3/4 cup (180 ml) hot brewed coffee or hot water
Chocolate Soak
- 6 oz (170 g) semisweet chocolate, finely chopped
- 3/4 cup (180 ml) heavy cream
- 1 tablespoon (14 g) unsalted butter
Glossy Chocolate Topping
- 8 oz (227 g) semisweet chocolate, finely chopped
- 3/4 cup (180 ml) heavy cream
- 1 tablespoon (14 g) unsalted butter
- 1/2 teaspoon vanilla extract
Finishing
- 2 tablespoons finely chopped semisweet chocolate
- 2 tablespoons crushed chocolate cookie crumbs
- 1 tablespoon white chocolate shavings
Instructions
- Preheat the oven to 350°F (175°C). Lightly grease a 9×13-inch metal baking pan. For easier removal, line the bottom with parchment paper while leaving some overhang on two sides.
- In a large bowl, whisk together the flour, sugar, natural cocoa powder, baking soda, baking powder, and salt. Break up any visible cocoa lumps.
- In a separate bowl, whisk the eggs, whole milk, vegetable oil, and vanilla extract until evenly combined.
- Pour the wet mixture into the dry ingredients. Mix just until most dry streaks disappear. Do not overmix.
- Gradually pour in the hot coffee or hot water while stirring. The batter will become quite thin. This is normal. Do not add additional flour.
- Pour the batter into the prepared pan. Bake for 28–34 minutes. Begin checking at 28 minutes. The cake is ready when the center is set and a toothpick inserted near the center comes out with a few moist crumbs but no raw batter.
- Place the pan on a wire rack and allow the cake to rest for 5–10 minutes. Keep the cake inside the pan.
- While the cake is still warm, use a wooden skewer, chopstick, or narrow handle of a wooden spoon to make small holes roughly 1 to 1 1/2 inches apart. Push them most of the way through the cake without scraping the bottom of the pan.
- To make the chocolate soak, place 6 oz finely chopped semisweet chocolate in a heat-safe bowl. Heat 3/4 cup heavy cream until steaming with tiny bubbles appearing around the edge. Do not aggressively boil it.
- Pour the hot cream over the chocolate. Leave undisturbed for 2 minutes. Add 1 tablespoon butter, then gently stir from the center outward until smooth.
- Slowly spoon the warm chocolate mixture across the warm cake. Direct some of it into the holes while distributing the rest evenly over the surface.
- Let the soaked cake rest for 20–30 minutes.
- For the topping, place 8 oz chopped semisweet chocolate in a clean heat-safe bowl. Heat the remaining 3/4 cup heavy cream until steaming, then pour it over the chocolate.
- Wait 2 minutes. Add 1 tablespoon butter and 1/2 teaspoon vanilla. Stir gently until smooth and glossy.
- Let the topping cool only until it is thick enough to spread but still fluid. Spread it across the cake with an offset spatula or the back of a spoon. Make broad, loose swirls like those visible in the reference cake.
- While the topping is still soft, lightly scatter chopped chocolate, chocolate cookie crumbs, and white chocolate shavings across the surface.
- Let the cake set for about 30 minutes before slicing. Use a sharp knife and wipe the blade between cuts for cleaner squares.
Notes
- Cocoa: Use natural unsweetened cocoa powder for this exact formula rather than automatically substituting Dutch-process cocoa.
- Coffee: Hot coffee adds roasted depth to the chocolate flavor. Hot water can be used instead.
- Thin batter: A relatively thin batter is expected after adding the hot liquid.
- Do not overbake: Begin checking at 28 minutes. A few moist crumbs on the tester are desirable.
- Hole spacing: More holes are not better. Small openings about 1–1 1/2 inches apart provide chocolate pockets without weakening the cake excessively.
- Ganache texture: Finely chop the chocolate so the hot cream can melt it evenly.
- Glossy appearance: Spread the final ganache while it remains soft and fluid. Waiting too long will produce a thicker, less glossy finish.
- Visual finish: Use only a light scattering of cookie crumbs, chopped dark chocolate, and white chocolate shavings. The glossy chocolate surface should remain clearly visible.
- Serving: For the soft, fudgy appearance in the reference image, serve at cool room temperature rather than refrigerator-cold.
- Prep Time: 25 minutes
- Additional/Rest Time: About 55–70 minutes
- Cook Time: 28–34 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American