Preheat your oven to 350°F (175°C). Grease and flour two 8-inch round cake pans.
In a large mixing bowl, sift together the flour, sugar, baking powder, baking soda, salt, and the star ingredient.
In a separate bowl, whisk together the buttermilk, vegetable oil, eggs, and vanilla extract until completely smooth.
Gradually pour the wet ingredients into the dry ingredients, mixing on low speed until just combined.
Carefully stream the hot espresso into the batter, mixing gently to bloom the chocolate flavors.
Divide the batter evenly between the prepared pans. Bake for 30-35 minutes until a skewer inserted in the center comes out clean.
Allow cakes to cool in pans for 10 minutes before transferring to wire racks to cool completely.
