Champagne Cake With Buttercream Icing

Preheat oven to 350 degrees F (175 degrees C). Grease and flour one 9-inch round cake pan and one 9x13-inch rectangular cake pan. (5 minutes)

In a very large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt until evenly combined. (2 minutes)

Add the milk, 1 cup shortening, 1/2 cup champagne, vanilla extract, and red food coloring (if using). Beat on low speed for about 30 seconds until just combined, scraping down the bowl constantly. Increase speed to medium and beat for 2 minutes. (3 minutes)

Add the unbeaten egg whites and beat on medium speed for an additional 2 minutes. The batter may appear slightly curdled, which is normal. (2 minutes)

Spread 2 3/4 cups of batter into the prepared 9-inch round pan and pour the remaining batter into the 9x13-inch rectangular pan. (3 minutes)

Bake at 350 degrees F (175 degrees C) for 30 to 35 minutes for the round cake and 40 to 45 minutes for the rectangular cake, or until a wooden skewer inserted into the center comes out clean. (40 minutes)

Cool the cakes in the pans on wire racks for 10 minutes, then carefully invert them onto the racks to cool completely. (1 hour)

To make the frosting: In a large bowl, beat together the 3/4 cup shortening and softened butter until light and fluffy. (3 minutes)

Beat in 1 tablespoon of champagne until well combined. (1 minute)

Gradually beat in the sifted confectioners' sugar, a cup at a time, until fully incorporated and smooth. If desired, add a few drops of red food coloring for a delicate tint. If the frosting is too thick, beat in additional champagne, one tablespoon at a time, until you reach a spreadable consistency. (5 minutes)

Assembling the cake: If creating a tiered cake, use cardboard circle patterns of 4 and 6 inches to cut one 4-inch and one 6-inch cake layer from the 9x13 inch cake. Drizzle 1 tablespoon of champagne over the top of each round cake layer for added moisture and flavor. (10 minutes)

Place the 9-inch cake layer on a serving plate or cake stand; frost the sides and top with buttercream frosting. Carefully center the 6-inch cake layer on top of the 9-inch cake. Frost the sides and top of the 6-inch layer. Repeat with the remaining 4-inch cake layer, if using. (20 minutes)

Decorate the cake with edible carnations or other edible flowers. For an extra touch, tint any remaining frosting with food coloring and pipe decorative swirls or borders. (15 minutes)