Sliced Chocolate Cakes Recipe

Prepare oven and pans

Preheat oven to 350°F (175°C). Grease a 9x13-inch baking pan or two 8- or 9-inch round cake pans with 1 tablespoon butter and dust with 1 tablespoon cocoa powder, tapping out excess.

Combine dry ingredients

In a large bowl, whisk together 2 cups all-purpose flour, 1.75 cups granulated sugar, 3 tablespoons unsweetened cocoa powder, 2 teaspoons baking powder, 1 teaspoon baking soda, and 1 teaspoon fine salt until evenly distributed.

Add wet ingredients

Add 2 large eggs, 1 cup whole milk, 1/2 cup vegetable oil, and 1 teaspoon vanilla extract to the dry mixture. Beat with a hand mixer or whisk for about 2 minutes until the batter is smooth and slightly aerated.

Thin the batter

Stir in 1 cup boiling water in two additions, mixing gently until combined. The batter will be thin — this yields a moist, tender crumb.

Bake

Pour batter into the prepared pan(s) and smooth the top. Bake in the preheated oven: 9x13 pan for 30–35 minutes, or 8–9 inch rounds for 25–30 minutes, until a toothpick inserted into the center comes out with a few moist crumbs. Rotate pans halfway through if your oven bakes unevenly.

Cool

Remove cakes from oven and set on a wire rack. Let cakes cool in the pan for 10–15 minutes, then invert onto the rack to cool completely (about 1 hour total) before glazing and slicing to prevent glaze from sliding off warm cake.

Warm cream and melt chocolate

Place 8 oz chopped semi-sweet chocolate in a heatproof bowl. In a small saucepan, warm 1/4 cup heavy cream with 2 tablespoons unsalted butter, 1 tablespoon light corn syrup, and 1/8 teaspoon fine salt over medium-low heat just until steam appears and butter is melted; do not boil.

Emulsify glaze

Pour the warm cream mixture over the chopped chocolate. Let sit for 1 minute, then whisk gently from the center until smooth and glossy. If necessary, microwave in 10-second bursts, stirring between, until fully melted and smooth.

Cool to spreadable temperature

Let glaze cool at room temperature for 10–15 minutes, stirring occasionally, until it thickens slightly and can be poured but will hold a thin layer on the cake surface.

Glaze the cake

Place the cooled cake on a wire rack set over a sheet pan to catch drips. Pour the glaze evenly over the center of the cake and use an offset spatula to spread it to the edges, letting some glaze drip down the sides for a clean finish. For a layered cake (if using rounds), stack layers with a thin crumb coat of glaze or extra frosting between them before glazing the whole cake.

Set the glaze

Allow the glaze to set at room temperature for 20–30 minutes. For a slightly faster set, refrigerate the cake uncovered for 10–15 minutes, but avoid prolonged refrigeration which can dull shine.

Slice

Using a long serrated knife or a large chef's knife, slice the cake into even pieces. For clean cuts, wipe the knife blade between cuts with a warm, dry towel. For thin 'sliced chocolate cakes' portions, aim for 12–16 slices from a 9x13 pan or 10–12 slices from two 8–9 inch rounds.

Finish and serve

Transfer slices to plates. Optionally dust with 1 tablespoon powdered sugar or add a dollop of whipped cream. Serve at room temperature.