Preheat oven to 350 F (176 C) and prepare two 8 inch round cake pans with a light coating of non-stick baking spray. Line the bottoms with parchment paper and wrap the outside of the pans with 'even-bake' strips if applicable.
In a large bowl, hand whisk together the flour, baking powder, baking soda, salt, cinnamon, nutmeg, cloves and espresso powder. Set aside.
Stir together the sifted cocoa powder, coffee, cooled brown butter, and oil with a spatula until smooth.
Fit the mixer with the paddle attachment and on low speed add the dark brown sugar and mix until incorporated. Scrape the bottom and sides of bowl as needed.
Mix in the eggs and egg yolks one at a time until batter is smooth and shiny.
Next, spoon in ⅓ of the flour mixture, alternating with ⅓ of the sour cream continuing on low speed until smooth. Scrape bottom and sides of mixing bowl as needed with a rubber spatula.
Transfer cake batter evenly into the prepared pans. Weigh the filled pans to be exact.
Place pans on the middle rack of the oven and bake for 30-33 minutes until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Set the pans on a wire cooling rack to cool completely.
Carefully invert the pans to remove layers, peel away parchment paper and set aside for assembly. Option to wrap layers in plastic wrap and freeze for 10 minutes to help with spreading frosting.