Preheat and Prepare:
Preheat your oven to 325°F (163°C). Line three 8-inch cake pans with parchment rounds and generously spray the parchment and sides of the pans with nonstick cooking spray.
Make the Coffee-Cocoa Mixture:
In a glass measuring cup, whisk together the hot coffee and cocoa powder. Cover and let the mixture stand for 5 minutes.
Mix the Dry Ingredients:
In a medium mixing bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon (if using).
Prepare the Wet Ingredients:
In a large mixing bowl, whisk together the sugar, vegetable oil, and melted butter until well combined. Add the eggs and egg yolk, whisking for about 20 seconds until the mixture is very well combined.
Whisk in the buttermilk, vanilla extract, and red gel food coloring until smooth. Add the vinegar and the coffee-cocoa mixture, whisking to combine.
Combine and Bake:
Using a fine mesh sieve, sift the flour mixture into the wet batter in three additions, whisking until each addition is fully incorporated.
Divide the batter equally among the prepared pans. Tap the bottoms of the pans on the counter several times to release any air bubbles.
Bake for 25-30 minutes, or until a cake tester or toothpick inserted into the center comes out clean. The cakes might look slightly spongy on top, which is normal. Place the cake pans on cooling racks. Once the pans are cool enough to touch, run a thin knife around the edges to loosen the cakes, then invert them onto the wire racks to cool completely.
Make the Cream Cheese Frosting:
In the bowl of a stand mixer fitted with the paddle attachment, beat the cream cheese and butter on medium-high speed until very light, creamy, and smooth. Scrape down the sides and bottom of the bowl to ensure no clumps remain.
Add the vanilla extract and beat until combined. On low speed, gradually add the sifted powdered sugar and beat until the frosting is fluffy, about 3 minutes. If the frosting is too thick, add a splash of milk or cream. If it’s too thin, add more sifted powdered sugar.
Assemble the Cake:
Place one cake layer flat-side up on a cake plate or pedestal. Tuck strips of baking paper under the cake edges to keep the plate clean.
Use about a third of the frosting to fill the bottom cake layer, then top with the second cake layer and repeat. Place the final cake layer flat-side up and use the remaining frosting to ice the entire cake.
Serve and Enjoy:
Once frosted, serve your Red Velvet Cake and enjoy the rich, moist layers with creamy frosting!