Heat the oven to 350°F. Grease and flour four 8-inch round cake pans.
In a large bowl, sift together the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Stir until evenly combined.
In a separate bowl, whisk the buttermilk, oil, eggs, and vanilla extract until smooth.
With the mixer on low speed, gradually add the wet mixture to the dry ingredients. Mix just until combined.
Slowly pour in the hot coffee and mix on low until the batter is smooth, scraping the bottom of the bowl once.
Divide the batter evenly among the prepared pans. Bake for 30 to 40 minutes, or until a toothpick inserted in the center comes out mostly clean.
Cool the cakes in the pans for 30 minutes, then turn them out onto wire racks to cool completely. Chill the cooled layers for at least 30 minutes before assembling.