1. preheat your oven to 350°f/175°c. grease three 9-inch cake pans. 2. Sift together the all-purpose flour, light brown sugar, and unsweetened cocoa powder in a large mixing bowl. 3. Add the baking soda, baking powder, and salt to the bowl with the sifted dry ingredients. whisk everything together until well combined. 4. Mix the espresso powder into the hot water and set aside. 5. Whisk together the eggs, buttermilk, melted butter, canola oil, and vanilla until smooth in another mixing bowl. 6. Add the espresso mixture and mix until combined. 7. Add the wet and dry ingredients to mix until just combined. be careful not to overmix, which can result in a dense cake.