Center a rack in the oven and preheat to 350 (F). Prepare two 8-inch cake pans by spraying generously with cooking spray and lining the bottom of each pan with a parchment paper circle; spray the parchment paper as well and set aside.

In a large bowl, whisk together 1 1/4 cups all-purpose flour, 1 cup granulated sugar, 3/4 cup Dutch-processed cocoa powder, 1 teaspoon baking powder, 1 teaspoon baking soda, and 1/2 teaspoon kosher salt until combined. Add 1 cup melted butter, 2 large eggs, 1 cup buttermilk, 1 cup coffee, and 1 teaspoon pure vanilla extract and continue whisking until the batter is smooth.

Divide the batter evenly the two prepared cake pans and transfer to the preheated oven to bake for 30 minutes, or until the top of the cakes bounce back when gently poked and a skewer inserted into the center of each cake comes out with few crumbs. Transfer to a wire rack and let the cakes cool in their pans to room temperature completely before frosting.