Preheat your oven to 350°F (175°C). Prepare three 9-inch round baking pans by greasing them and lining with parchment paper.

In a large mixing bowl, whisk together granulated sugar, all-purpose flour, unsweetened cocoa powder, baking powder, baking soda, and salt until well combined.

Create a well in the center of the dry ingredients. Add the whisked eggs, buttermilk, canola oil, and pure vanilla extract. Mix until smooth.

Dissolve instant espresso powder in hot coffee and mix into the batter until combined.

Evenly divide the batter among the prepared baking pans and bake for 26-30 minutes.

Allow the cakes to cool in their pans for 10-15 minutes, then invert onto wire racks to cool completely.

In a mixing bowl, beat the unsalted butter until creamy. Gradually add powdered sugar and cream or Kahlua, beating until light and fluffy.

Once cool, level the cakes, stack them with frosting in between, and frost the top and sides.