Red Velvet Cake

Step 1
Preheat the oven to 350 degrees F (175 degrees C). Grease two 9-inch round pans.

Step 2
Make the cake: Beat 1 1/2 cups sugar and shortening together in a large bowl with an electric mixer until light and fluffy. Add eggs one at a time, beating well after each addition. Combine red food coloring and cocoa to make a paste; add to creamed mixture.

Step 3
Mix buttermilk, salt, and 1 teaspoon vanilla together in a small bowl. Add flour, alternating with buttermilk mixture, mixing just until incorporated. Mix vinegar and baking soda together; gently fold into cake batter and pour into prepared pans.

Step 4
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 30 minutes. Cool on a wire rack for 5 minutes. Run a table knife around the edges to loosen. Invert carefully onto a serving plate or cooling rack. Let cool, about 30 minutes.

Step 5
Make the icing: Heat milk and flour in a saucepan over low heat, stirring constantly, until thick. Set aside to cool completely.

Step 6
Meanwhile, beat sugar, butter, and vanilla together in a large bowl with an electric mixer until light and fluffy. Add cooled flour mixture and beat until frosting is a good spreading consistency. Frost cake layers when completely cool.