Preheat oven to 325°F. Lightly grease three 6” round cake pans with cooking spray and line the bottoms with parchment paper circles.

In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and the sugar until fluffy and light in color, about 3-5 minutes.

Slowly add the eggs one at a time and vanilla, combining well after each addition. Mix in the cocoa then scrape the bowl well with a rubber spatula. Mix on high for an additional 30 seconds until the mixture is smooth.

Combine the flour, baking soda, and salt then combine the buttermilk, red food coloring, and vinegar. Alternate adding the flour and buttermilk mixtures, starting and ending with the flour. Mix until just combined after each addition and scrape down the bowl a few times during the process.

Divide the batter evenly between the three cake pans. Bake for 25-30 minutes, or until the cake springs back to the touch or a toothpick comes out clean.

Cool the cakes until they are cool enough to handle then remove them from the pans.

In a small saucepan, combine the water and cornstarch and cook over low heat until the mixture thickens and starts to boil. Strain the slurry mixture, press plastic wrap directly onto the top, and set aside to cool to room temperature.

In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and the sugar until fluffy and light in color, about 5 minutes. Add the vanilla and mix.

Switch to the whisk attachment. Once the cornstarch slurry has cooled to room temperature, add a little at a time to the mixing bowl, while running on medium speed. After all the slurry has been added, turn the mixer on high speed and whip until smooth.

Once the cakes are cool, slice the top off of each cake layer to make them level then slice each layer in half horizontally, to create 6 even layers.

Break up the cake tops into small pieces and place them on a baking sheet. Bake at 300°F for about 5 minutes, until they start to dry out slightly. Allow the cake pieces to cool then rub the pieces between your fingers to create coarse crumbs. Set aside.

Place the first cake layer, cut side up on a cake board or cake stand. Add about ½ cup of frosting and spread it out to the edges. Place your next cake layer on top, gently press down, and repeat the same process for the remaining layers. On the last layer, place the cake layer cut-side down.

Crumb-coat the cake entire cake with a thin layer of icing and refrigerate for about 20-30 minutes. Apply a final thicker layer of frosting all over the top and sides of the cake and smooth it with an offset spatula.

Turn the spatula horizontally and using the top rounded part, lightly drag it along the sides of the cake starting at the bottom and slowly working up to the top, to create a pattern on the sides of the cake. Press some of the red velvet cake crumbs up the sides of the cake.

Fit a piping bag with a star tip and fill it with any remaining icing. Pipe rosettes on the top of the cake and finish with a sprinkle of more red velvet cake crumbs. Slice and enjoy!