Chocolate Cake Slice Recipe

Prepare

Preheat the oven to 350°F (175°C). Grease and line an 8x8-inch square baking pan (or a 9-inch round) with parchment, leaving an overhang for easy removal. Lightly grease the parchment.

Dry ingredients

In a large bowl, whisk together the all-purpose flour, granulated sugar, unsweetened cocoa powder, baking powder, baking soda, and fine salt until evenly combined and free of lumps.

Wet ingredients

In a separate medium bowl, whisk the eggs until combined. Add the whole milk, neutral oil, and vanilla extract and whisk until smooth.

Combine batter

Pour the wet mixture into the dry ingredients and stir with a spatula or wooden spoon until just combined and no large streaks of flour remain. Do not overmix.

Add hot liquid

Slowly pour the hot brewed coffee or hot water into the batter while gently folding it in. The batter will thin; this is normal and yields a moist cake. Scrape the bowl sides and mix until homogeneous.

Bake

Pour the batter into the prepared pan, smoothing the top. Bake in the preheated oven for 28–35 minutes for an 8x8 pan (adjust 3–8 minutes less for a 9-inch round), or until a toothpick inserted in the center comes out with a few moist crumbs but not raw batter and the cake springs back lightly when pressed.

Cool

Remove the cake from the oven and set the pan on a wire rack. Let cool in the pan for 10–15 minutes, then run a knife around the edges and lift the cake out using the parchment overhang. Transfer to the rack to cool completely before glazing. If using simple syrup, proceed while cake is still slightly warm.

Make syrup (optional): In a small saucepan, combine 1/4 cup granulated sugar and 1/4 cup water. Bring to a simmer over medium heat, stirring until the sugar dissolves. Remove from heat and stir in the optional dark rum or 1 tsp vanilla extract. Let cool slightly. While the cake is still warm, brush the syrup evenly over the top to add moisture and a flavor boost.

Warm cream

Place the chopped chocolate in a heatproof bowl. In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer and small bubbles form at the edges—do not boil.

Make ganache

Pour the hot cream over the chopped chocolate and let sit for 1–2 minutes to soften. Gently stir from the center outward until the mixture is smooth and glossy. If using, whisk in the unsalted butter for added shine and a silkier texture.

Glaze cake

Place the cooled (or slightly warm) cake on a wire rack set over a sheet pan to catch drips. Pour the ganache over the center of the cake and tilt or gently spread with an offset spatula so the ganache covers the top and drips a little over the sides. Let the ganache set at room temperature for 30–60 minutes (or refrigerate 10–15 minutes) before slicing.

Slice: Once ganache is set, transfer the cake to a cutting board if desired. Use a sharp knife dipped in hot water and wiped dry between cuts to get clean slices. Serve at room temperature or slightly chilled.

Store: Keep leftover cake covered at room temperature for up to 2 days, or refrigerate in an airtight container for up to 5 days. If refrigerated, bring to room temperature before serving for best texture. Ganache can be warmed slightly in the microwave (5–10 seconds) to regain a glossy appearance.