Red Velvet Cake with Buttercream Frosting

This classic cake is hard to resist. The bright color combination makes it perfect for Christmas and Valentine's Day, as well as birthday parties. A thick, cooked mixture of flour and milk gives the glaze a thicker appearance, while maintaining a sufficient amount of fat.
Preheat the oven to 350 degrees.To prepare the cake, brush 2 (8-inch) round cake pans with cooking spray; line the bottom of the pans with waxed paper. Brush waxed paper with cooking spray; set aside the molds.Put the granulated sugar and baking powder in a large bowl; beat with a mixer on medium speed for 5 minutes or until smooth. Add egg substitute; beat well. Combine the cocoa and food coloring in a small bowl, stirring with a whisk; add to the sugar mixture, mixing thoroughly until smooth.Lightly pour the cake flour into dry measuring cups and smooth with a knife. Combine the cake flour and 1/2 teaspoon salt, stirring with a whisk. Add the flour mixture and buttermilk alternately to the sugar mixture, starting and ending with the flour mixture; stir after each addition. Add 1 teaspoon vanilla. Combine the vinegar and baking soda; add to the batter, mixing well. Pour the batter into the prepared molds. Tap the molds sharply on the countertop once to remove any air bubbles. Bake at 350 ° C for 25 minutes or until a wooden stick inserted in the middle comes out clean. Cool in the pan for 10 minutes on a wire rack; remove from the pan. Carefully remove the wax paper; cool completely on a wire rack.To make the frosting, combine the milk and flour in a small heavy saucepan over medium-high heat. Cook for 3 minutes or until the mixture is a very thick paste, stirring constantly with a whisk. Spoon into a bowl; cover the surface with plastic wrap. Refrigerate for 45 minutes or until completely cooled. Put the butter in a medium bowl and beat with a mixer on medium speed until creamy. Add 2 teaspoons of vanilla, 1/8 teaspoon of salt, and the cooled flour mixture; beat until smooth. Gradually add the powdered sugar, whisking until smooth (do not interrupt).Place 1 cake on a plate; spread with 1/3 cup icing. Top with another cake. Spread the remaining icing on the top and sides of the cake. Keep the cake loosely covered in the refrigerator.