Old-Fashioned Sheet Cake

A Mr. T birthday cake.

The humble rectangular pan is transformed into a hero when baking Granny’s Old-Fashioned Sheet Cake. This large flat cake is rich and moist, iced with a silky buttercream frosting. It’s great for when you need to serve a delicious dessert to lot of people.

And for aspiring pastry artists, there is plenty of surface area on a sheet cake for decoration and a personal message. Edible iced flowers are a popular addition but the sky is the limit. Its adaptability and tastiness make it perfect for birthday parties, graduation celebrations, or any other type of festivity!


3 cups (354 grams) cake flour
1 12 cups (300 grams) granulated sugar
1 tablespoon baking powder
12 teaspoon baking soda
34 teaspoon salt
1 cup (230 grams) unsalted butter, room temperature
1 cup (240 grams) whole milk, room temperature
3 large eggs, room temperature
1 tablespoon vanilla extract
3 cup (80 grams) sour cream, room temperature

Buttercream Frosting
1 cup (230 grams) unsalted butter, room temperature
4 12 cups (540 grams) powdered sugar
13 cup (75 grams) heavy cream
2 teaspoons vanilla extract
18 teaspoon salt


  • 1. Preheat oven to 350 F (175 C). Grease a 9x13 baking pan and set aside.

  • 2. In a large bowl, add room temperature butter and granulated sugar. Beat until creamed. Add vanilla and eggs, one at a time, and mix until smooth.

  • 3. In a separate bowl, sift together dry ingredients: cake flour, baking powder, and salt. Add half of the dry ingredients to butter mixture. Mix until just combined. Add half of milk, again mixing until just combined. Repeat once more to add remaining dry ingredients and milk.

  • 4. Pour batter into prepared baking pan and spread into an even layer. Bake for 32-38 minutes or until the cake is baked through in the center and a toothpick comes out clean.

  • 5. Remove cake from oven and allow to cool completely in the pan on a wire cooling rack.
Buttercream Frosting
  • 1. In a large bowl, add room temperature butter and beat until creamy. Add powdered sugar and slowly mix until ingredients are fully combined. Then, whip at high speed for 2-3 minutes until fluffy.

  • 2. Add heavy cream, vanilla extract, and salt. Whip for an additional 3-4 minutes, or until light and fluffy. Add additional heavy cream as needed to reach desired consistency.

  • 3. Spread frosting in an even layer onto cooled cake. Don't frost the cake until it is completely cooled or the frosting will melt.

  • 4. Cover leftover cake tightly and store in the refrigerator for up to 5 days.

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