Velvety Chocolate Swirl Cake

Preheat the oven to 325°F (162°C) and lightly mist two 8-inch diameter cake pans with non-stick spray. Line the bottom with circles cut from parchment paper.

In a large mixing bowl, combine all-purpose flour, sugar, baking powder, baking soda, and kosher salt.

Add softened butter to the flour mixture and mix on medium-low speed until it resembles damp sand (about 1 minute).

Add the eggs, one at a time, incorporating each egg fully before adding the next one. Scrape the bottom and sides of the bowl with a silicone spatula after each addition.

Stir in the sour cream until smooth.

Scrape the bottom and sides of the bowl with a silicone spatula once again, then add the milk and vanilla extract.

Beat the batter on medium speed for about 1-1.5 minutes to aerate the batter and build the cake's structure.

In a separate bowl, mix the cocoa powder and hot water until smooth, then pour half of the cake batter into the cocoa mixture and fold until well-combined.

Transfer the chocolate and vanilla batters alternately into the prepared pans, creating a marbled effect by lightly swirling the batters together using a butter knife or a small spatula.

Bake the cake layers for 35-40 minutes, until a toothpick inserted in the center of the cake comes out clean or with a few moist crumbs.

Allow cakes to cool on a wire rack for 20 minutes before removing them from their pans, then let them cool completely before assembling and frosting with your desired frosting.