Start by preheating the oven to 350°F and preparing your cake pans with butter and flour. In one bowl, sift together flour, salt, and baking soda to avoid lumps. In another bowl, cream the butter and sugar until light and fluffy. This step ensures your cake has a soft and airy base. Add eggs one at a time, then vanilla, mixing until fully combined.
Sift cocoa powder into the butter mixture and blend well. In a measuring cup, stir together buttermilk, vinegar, and food coloring. This gives the cake its iconic red color while keeping the crumb moist. Gradually add half the flour mixture, then half the buttermilk mixture. Repeat until both are used up, mixing just until smooth. Overmixing can make the cake tough.
Divide the batter evenly into the cake pans and bake for 30–35 minutes. The cakes are ready when the tops spring back to touch. Allow them to cool in the pans for 10 minutes before transferring them to a wire rack. Cooling fully is important so the frosting doesn’t melt when you assemble the cake.
In a large bowl, beat cream cheese and butter until smooth and fluffy. Add vanilla and a pinch of salt. Slowly sift in confectioners sugar, mixing on low to prevent lumps. Once combined, increase speed and beat until light and fluffy. Save some frosting in a piping bag for decorating later.
Place the first cake layer on a stand and spread ½ cup frosting evenly. Add the second layer, repeat with frosting, then top with the final layer. Spread the remaining frosting over the top and sides of the cake. Use a spatula to smooth it out. Pipe decorations around the edges for a polished finish. Chill for 1 hour so the frosting sets before serving.