Cake Ingredients

• 1/2 cup water
• 1/2 granulated sugar
• 1 tbsp dark or dutch-processed cocoa powder
• 2 1/2 cups all-purpose flour (325g)
• 2 1/2 cups granulated sugar (500g)
• 1 cup dark or dutch processed cocoa powder (94g)
• 2 1/2 tsp baking powder (10g)
• 2 tsp baking soda (12g)
• 1 1/4 tsp salt (8g)
• 1 tsp instant espresso (1g) (optional)
• 1 cup warm water (300g)
• 1 1/4 cup full-fat sour cream, at room temperature (319g)
• 1/2 cup vegetable or canola oil (138g)
• 3 eggs (140g)
• 2 tsp vanilla extract (10g)

Cake Instructions

1. To make simple syrup, stir together 1/2 cup hot water, 1/2 cup sugar and 1 tbsp of cocoa until well blended. Set aside to cool. This will be brushed onto the cake layers right before cake assembly.
2. Preheat oven to 350°F (175°C). Line three 9-inch round cake pans with parchment paper.
3. In a large bowl, sift together the flour, sugar, cocoa, baking powder, baking soda, salt, and espresso.
4. Add the warm water, sour cream, oil, eggs, and vanilla. Beat on medium speed until smooth.
5. Divide batter between pans and bake for 30–35 minutes, or until a toothpick comes out clean.
6. Cool in pans for 10 minutes, then turn out onto wire racks to cool completely.

Frosting Ingredients

• 2.5 cups (5 sticks) unsalted butter, room temperature (565g)
• 1 1/4 cup dark baking cocoa, sifted (125g)
• 1 1/4 tsp vanilla extract (5g)
• 1/2 tsp fine salt (3g)
• 6 1/4 cups powdered sugar (781g)
• 1 cup heavy whipping cream, room temperature (225g)
• 1 2/3 cups dark chocolate chips, melted and cooled (287g)
• 1 cup mini chocolate chips (optional)

Frosting Instructions

1. Beat butter on medium speed for 30 seconds until smooth.
2. Mix dark cocoa powder, vanilla extract, and salt on low until combined, scraping the bowl as needed.
3. Gradually mix in powdered sugar and heavy cream on a low speed.
4. Mix in melted and cooled dark chocolate chips at low speed until fully blended. The chocolate should be fluid but not hot—let it sit for 10 minutes before adding. Scrape the bowl’s sides and bottom with a spatula to avoid lumps. Cover with plastic wrap to prevent crusting and set aside.

Assembly of cake

• Stack and frost the cake layers on a greaseproof cake board or flat plate, using a bit of chocolate buttercream to secure the first layer.
• Before you stack each cake layer, use a silicone brush to soak the top of the cake layer with chocolate simple syrup.
• Spread an even layer of chocolate buttercream on top of each cake layer as you stack them with a large offset spatula.
• Repeat with the remaining cake layers, then freeze the cake for about 10 minutes to firm up the buttercream and reduce crumbling, making it easier to frost.
• Cover the cake with an even layer of chocolate buttercream, smoothing it with a large spatula. It doesn’t need to be perfectly smooth!
• Carefully press mini chocolate chips into the frosting around the bottom of the cake, if desired.