Pride Flag Vanilla Sheet Cake with Buttercream Frosting

Pride Flag Vanilla Sheet Cake with Buttercream Frosting

This Pride rainbow cake is colorful, delicious, and sugar-free! 

By Thomas John of @thomasjohn26

Prep 35m

Cook 25m

Total 3h

Serve 8


Vanilla Sheet Cake Ingredients:

  • 3 cups cake flour
  • 1 ½ cups Purecane™ zero- calorie Baking Sweetener
  • 1 teaspoon baking powder
  • ½ teaspoon baking soda
  • 1 teaspoon salt
  • 1 cup (2 sticks) unsalted butter (cubed and softened to room temperature)
  • 1 Tablespoon pure vanilla extract
  • 1 cup whole milk (room temperature)
  • ⅓ cup sour cream (room temperature)
  • 3 large eggs (room temperature)


Whipped Vanilla Buttercream Ingredients:



Preheat the oven to 350 °F. Grease the bottom of a 9x13 inch cake pan and set aside.

Make the cake: 

  1. Sift the cake flour, Purecane™ zero-calorie Baking Sweetener, baking powder, baking soda, and salt in the bowl of a stand mixer or medium-sized mixing bowl. With the paddle attachment, beat the ingredients together on low speed for a few seconds to gently combine (can use a regular whisk, may need to whisk longer). Add the butter, vanilla, and ½ cup of milk. Mix until the dry ingredients are moistened (about 1 minute with a mixer). Stop the mixer and scrape down the sides and up the bottom of the bowl. The mixture will resemble a thick dough.
  2. Whisk the remaining milk, sour cream, and eggs together in a medium bowl. With the mixer running on medium speed, add the egg mixture in 3 additions, mixing for about 15 seconds after each addition. Stop the mixer and scrape down the sides and up the bottom of the bowl, then mix for about 15 more seconds until batter is completely combined. (avoid over-mixing, some small lumps are okay)
  3. Pour and spread batter evenly into the greased pan. Bake for around 20-25 minutes or until the cake is baked through. To test if the cake is finished baking, insert a toothpick into the center of the cake. If it comes out clean, it’s done. Allow cake to cool completely in the pan set on a wire rack. (cake must be completely cool before frosting, about 2 hours)

Prepare the frosting:

  1. With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add Purecane™ Confectioners Sweetener, vanilla extract, and half of the heavy cream. Beat on low speed for 30 seconds, then increase to medium-high speed and beat for 4 full minutes. Add ½ teaspoon of salt. Alternate between adding the Purecane™ Confectioners Sweetener and heavy cream to find the perfect consistency. Frosting should be extra fluffy.

Decorate the cake:

  1. To frost a design of your preference, evenly separate buttercream into the appropriate amount of bowls and use food coloring gel to make the desired colors for your design. Scoop buttercream into small sandwich bags and cut off a small hole on the corner of the bag to pipe frosting. Pipe frosting into the desired pattern and use an offset spatula or butter knife to flatten frosting and spread. Make sure the offset spatula or knife is warm and use nonstick spray on the tool to make sure it doesn't stick when spreading. Slice and serve. Enjoy!