The best chocolate cake

Ingredients:

Cakes

• 1 and 1/4 cups cocoa + extra for working with the dough
• 2 and 1/4 cups premium flour
• 2 and 1/4 teaspoons of baking soda
• 1 teaspoon baking powder
• 1 large egg, room temperature
• 2 large egg yolks, room temperature
• 2 and 1/4 cups light brown sugar
• 1 and 1/4 cups sour cream, room temperature
• 2/3 cup vegetable oil
• 1 tbsp vanilla extract
• 1 and 1/4 teaspoons coarse salt

Glaze

• 340 g semi-sweet chocolate granules or chopped semi-sweet chocolate (64% cocoa)
• 450 g unsalted butter, room temperature
• 3/4 teaspoon coarse salt
• 2 cups powdered sugar
• 4 tsp cocoa powder
• 1 tbsp vanilla paste or vanilla extract

Preparation:

1. Cakes:
   
   Position a rack in the middle of the oven and preheat the oven to 350°F (175°C). Lightly spray two 9-inch (22-cm) round cake pans with cooking spray. Line the bottom of each pan with a circle of parchment paper and lightly spray the paper with cooking spray. Dust the bottom and sides of each pan with alkalized cocoa powder, shaking off any excess.
2. Sift the cocoa powder, flour, baking soda, and baking powder into the bowl of a stand mixer. Mix on low speed until evenly combined. Add the eggs, egg yolks, brown sugar, sour cream, oil, vanilla, salt, and 1 cup of hot water. Beat on medium speed until smooth, about 3 minutes.
3. Divide the batter evenly among the prepared pans. Smooth the surface of the batter. Bake, rotating the pans halfway through, until a tester inserted into the center of the cake comes out clean, 35-45 minutes. Transfer the pans to a wire rack and let the cakes cool for 30 minutes. Run a knife along the sides of the cakes and invert them onto a wire rack. Remove the parchment and let the cakes cool completely.
4. Trim off any domed tops with a large serrated knife to flatten the cakes.
   
   Glaze:
   
   Melt the chocolate in a heatproof bowl set over a saucepan of simmering water. Remove the bowl from the water bath and let it cool to room temperature, about 30 minutes.
   
   In a large bowl, beat the butter and salt with a mixer on high speed until light and fluffy, about 2 minutes. Reduce the mixer speed to low, pour in the chocolate, and beat until combined. Gradually beat in the powdered sugar, cocoa powder, and vanilla. Increase the mixer speed to high and beat until light and fluffy, about 2 minutes.
5. Assembling the cake:
   
   Place one cake layer cut-side down on a serving plate. Spread 1.5 cups of frosting evenly. Place the remaining cake layer on top, cut-side down. Spread 1.5 cups of frosting on top. Cover the sides of the cake with 3/4 cup of frosting and smooth it out completely to create an even base layer. It's okay if some of the cake is showing through the frosting at this point. Refrigerate the cake for 30 minutes to allow the frosting to set.
6. Spread the remaining frosting over the top and sides, leaving decorative swirls.
   
   
   When measuring flour, spoon it into a dry measuring cup and remove any excess. Scooping flour directly from the bag with a measuring cup will compact it, resulting in dry baked goods.