Funfetti Sheet Cake with Vanilla Buttercream

A bright, tender vanilla sheet cake loaded with rainbow sprinkles and topped with a cloud of sweet vanilla frosting. This dairy-free, egg-free version is every bit as fun and nostalgic as the classic, baking up in a single 9×13 pan with a soft crumb that holds up beautifully under a thick swirl of buttercream. Perfect for birthdays, celebrations, or any time you need a cake that feeds a crowd and makes everyone smile. The frosting sets just firm enough to write a message on top, and the whole thing comes together without fuss.

By TasteBuds

Recipe details

Yield
12 people
Prep time
20 minutes
Cook time
30 minutes
Total time
1 hour 15 minutes

Ingredients

  • 2½ cups all-purpose flour
  • 1¾ cups granulated sugar
  • 1 tbsp baking powder
  • ½ tsp baking soda
  • ½ tsp salt
  • 1¾ cups unsweetened plant milk (almond, oat, or soy all work)
  • ½ cup vegetable oil
  • 1 tbsp white vinegar or apple cider vinegar
  • 1 tbsp vanilla extract
  • ½ cup dairy-free rainbow sprinkles (check the label for dairy-free status)
  • 1 cup vegan butter, softened to room temperature (for frosting)
  • 4 cups powdered sugar (for frosting)
  • 3 to 4 tbsp unsweetened plant milk (for frosting)
  • 1 tsp vanilla extract (for frosting)
  • ¼ cup dairy-free rainbow sprinkles (for topping)

Instructions

  1. Preheat oven to 350°F (175°C).
  2. Line a 9×13 inch baking pan with parchment paper, leaving an overhang on two sides for easy lifting later.
  3. In a large mixing bowl, whisk together 2½ cups all-purpose flour (300 g), 1¾ cups granulated sugar (350 g), 1 tbsp baking powder (15 g), ½ tsp baking soda (2.5 g), and ½ tsp salt (2.5 g) until evenly combined.
  4. In a medium bowl, whisk together 1¾ cups unsweetened plant milk (420 ml), ½ cup vegetable oil (120 ml), 1 tbsp white or apple cider vinegar (15 ml), and 1 tbsp vanilla extract (15 ml).
  5. Pour the wet ingredients into the dry ingredients and whisk until just combined. A few small lumps are fine, don't overmix.
  6. Gently fold in ½ cup dairy-free rainbow sprinkles (85 g) with a spatula, stirring just enough to distribute them.
  7. Pour the batter into the prepared pan and spread it evenly with a spatula.
  8. Bake for 28 to 32 minutes, until a toothpick inserted in the center comes out clean or with just a few moist crumbs, and the top springs back lightly when touched.
  9. Remove the cake from the oven and let it cool in the pan on a wire rack for 15 minutes.
  10. Use the parchment overhang to lift the cake out of the pan and onto the rack to cool completely, about 30 minutes.
  11. While the cake cools, make the frosting. In a large bowl, beat 1 cup softened vegan butter (225 g) with an electric mixer on medium speed until creamy and smooth, about 1 minute.
  12. Add 4 cups powdered sugar (480 g), 3 tbsp unsweetened plant milk (45 ml), and 1 tsp vanilla extract (5 ml). Beat on low speed until the sugar is incorporated, then increase to medium-high and beat for 2 to 3 minutes until light and fluffy. If the frosting is too thick, add the remaining 1 tbsp plant milk (15 ml) and beat again.
  13. Once the cake is completely cool, spread the frosting evenly over the top with an offset spatula or butter knife.
  14. Scatter ¼ cup dairy-free rainbow sprinkles (40 g) over the frosted cake.