To make the cake layers, preheat the oven to 350°F (176°C) and prepare three 8 inch cake pans with non-stick baking spray and parchment paper at the bottom.
In a large bowl, combine flour, cocoa powder, salt, baking soda, baking powder, granulated sugar, and brown sugar. Set aside.
In another bowl, mix eggs, sour cream, melted butter, and vanilla extract.
Add the wet ingredients to the dry ingredients and mix until well combined.
Mix the boiling water with the espresso granules and slowly add the hot coffee to the batter and mix until combined well. Scrape down the sides of the bowl as needed to make sure everything is incorporated.
Divide the batter evenly between the prepared cake pans and bake for 22-25 minutes, or until a toothpick comes out with a few moist crumbs.
Remove cakes from the oven and cool for 2-3 minutes, then remove from pan and transfer to a cooling rack to finish cooling.