Preheat your oven to 350°F (175°C). Line two 8-inch round cake pans with parchment paper and spray with nonstick spray.

In a medium bowl, mix Dutch-process cocoa and espresso powder. Add boiling water and whisk until smooth; let cool to room temperature.

In a large mixing bowl, sift together all-purpose flour, baking soda, fine sea salt, and light brown sugar.

In another bowl, whisk together sour cream, neutral oil, eggs, and vanilla extract until smooth and creamy.

Pour the wet ingredients into the dry mixture; stir just until combined. Slowly add the cooled cocoa mixture, stirring until smooth.

Divide the batter evenly between the prepared pans and bake for 32-35 minutes until a toothpick comes out with a few moist crumbs.

Cool the cakes in pans for 30 minutes, then turn out onto a wire rack to cool completely before frosting.