How to Make a Hidden Heart Cake

Pre-heat the oven to 350 Fahrenheit (180 Celsius). Grease and line a 9-inch x 5-inch (23-cm x 12-cm) loaf tin with parchment paper. Let the paper hang over the edges. Set aside.

Sift the flour, baking powder, baking soda and salt into a large mixing bowl. Stir in the sugar.

Add in the eggs, milk and vanilla bean extract. Pour in the melted butter and stir until just combined.

Add the finely ground espresso powder in with the boiling water. Stir to combine until dissolved.

Pour half the mixture into one of the loaf tins then set aside the mixing bowl with the remaining batter. Bake this loaf, until it rises and the top springs back when lightly pressed, about 30 to 35 minutes. If you insert a toothpick into the middle, it should come out clean. Remove from the oven and let the cake cool in the pan for 15 minutes.

Meanwhile, sift the 1.7 ounces (50 grams) of the dutch processed cocoa powder into the remaining batter set aside in the large mixing bowl. Stir it in until the mixture is evenly combined. Cover the bowl with a layer of plastic wrap or a kitchen towel and set the batter aside until the vanilla cake has finished baking and cooling.

When the vanilla cake has cooled for about 15 minutes, turn it out of the pan. Cut the cake into even slices about 1.5 inches (4 cm thick). You should get about 6-7 slices.

Pour half of the chocolate mixture set aside above into the loaf tin. Push the vanilla cake hearts into the batter so that they stand upright in a tightly packed row. Carefully pour over the remainder of the chocolate mixture over the vanilla cake hearts to cover.

While the cake is cooling, begin the chocolate buttercream frosting. Place the remaining 7 ounces (200 grams) of unsalted butter into the bowl of a stand mixer fitted with a beater attachment (you can also use hand held electric beaters). Beat on medium-low speed, for 1 minute, or until the butter is soft and malleable. Pause mixing and add in the powdered sugar, 1.4 ounces (40 grams) of dutch processed cocoa powder and 1 teaspoon of the finely ground espresso powder (if using). Continue to beat, on medium speed, until evenly incorporated and fluffy, about 3 minutes. Add in the heavy cream and vanilla bean extract and continue to beat for a further 2 minutes. Stop mixing and set aside for decorating.

Once the cake has cooled completely, use a rubber spatula to generously frost the top and sides of the cake with swoops and swirls of the chocolate buttercream. At this point, you can also decorate the cake however you would like! With fresh raspberries or strawberries, sprinkles, edible glitter or gold, heart decorations or even a drizzle or shavings of white chocolate. Once decorated, chill the cake to set the frosting for 30 minutes before serving.

Let the cake stand at room temperature for 15 minutes before slicing and serving! The cake will keep for 3 days stored in an airtight container in the refrigerator, or up to 1 month stored in the freezer. Make sure to defrost completely before eating.