Description

This structurally sound chocolate cake features a rich cocoa base and a silky turquoise Swiss meringue buttercream, perfect for supporting themed decorations. The combination of buttermilk and oil ensures a moist, reliable crumb that holds up beautifully during assembly and slicing for a professional birthday centerpiece.

Ingredients

300 g unbleached all-purpose flour
75 g cocoa powder, sifted
1 tsp baking soda
1 tsp baking powder
420 g granulated sugar (for cake batter)
4 large eggs, room temperature
125 ml canola oil
2 tsp vanilla extract
325 ml buttermilk
140 g dark chocolate (minimum 60% cocoa)
Corn syrup (for ganache gloss)
160 g granulated sugar (for buttercream)
4 large egg whites
225 g unsalted butter, softened
Turquoise gel-based food coloring

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Instructions

Preheat oven to 350°F (175°C) and grease two 8-inch or 9-inch round cake pans lined with parchment paper.
Sift the flour, cocoa, baking soda, and baking powder into a large bowl to aerate the dry ingredients.
In a stand mixer with a paddle attachment, beat 4 eggs and 420g sugar on medium for 3 minutes until thick, then slowly stream in the oil and vanilla.
Alternately add the dry ingredients and buttermilk to the egg mixture, starting and ending with flour, mixing until just combined.
Divide batter equally between pans and bake for 30 to 35 minutes, or until an internal temperature of 205°F (96°C) is reached.
Cool in pans for 10 minutes before transferring to a wire rack to reach room temperature.
Whisk 160g sugar and 4 egg whites in a heatproof bowl over a simmering water bath until the mixture hits 160°F (71°C).
Whip the egg white mixture in a stand mixer until stiff peaks form and the bowl is cool, then gradually add softened butter and turquoise gel.
Layer the cake with frosting, apply a crumb coat, chill for 20 minutes, then finish with a final frosting layer and a drip of chocolate ganache.

Notes

When decorating, ensure your ganache has cooled to approximately 85°F (29°C) before pouring to prevent the Swiss meringue buttercream from melting. Using a digital thermometer for both the cake crumb and the frosting base ensures consistent structural results every time. For the most vibrant turquoise color, always use gel-based pigments which provide deep color without thinning the consistency of your icing.

Prep Time: 45 mins
Cook Time: 35 mins
Category: Dessert
Method: Baking
Cuisine: American