With vinegar, buttermilk, and two ounces of food coloring.
From a box sold in Nampa, Idaho.
Red Velvet Cake (Magazine)
1-1/2 c. sugar
1/2 c. shortening
1 c. buttermilk
1 tsp. salt
1 tsp. vanilla
1 Tbsp. unsweetened cocoa
2 oz. red food coloring
2-1/2 c. flour (cake)
1-1/2 tsp. baking soda
1 Tbsp. vinegar
1 c. heavy cream
Set oven to 350 deg. In a large bowl, cream sugar and shortening. Add eggs and cream again, lightly. Add buttermilk, salt, vanilla, and cocoa; stir to combine. Add food coloring. Gradually add flour.
In a small bowl, mix baking soda and vinegar. Promptly add to batter and fold in slowly.
Pour batter into a greased and floured 10-inch springform pan. Bake 50 minutes.
Allow cake to cool, then slice it into 3 even layers, cutting rounded top from top slice. Crumble this small piece and use as a garnish later.
Whip cream, then fill layers, and frost top and side of cake. Garnish side with reserved crumbs. For scallop pattern, press crumbs against the cake with your palm.