Not-So-Perfect Birthday Sheet Cake (Printable Version)

Playful sheet cake with moist crumb, topped with whimsical swirls of frosting and bright sprinkles for any celebration.

# What You'll Need:

→ Cake

01 - 2 1/2 cups all-purpose flour
02 - 2 cups granulated sugar
03 - 1 tablespoon baking powder
04 - 1/2 teaspoon salt
05 - 1 cup whole milk, room temperature
06 - 3/4 cup unsalted butter, melted and slightly cooled
07 - 4 large eggs, room temperature
08 - 2 teaspoons vanilla extract
09 - 1/2 cup sour cream, room temperature

→ Frosting

10 - 1 cup unsalted butter, softened
11 - 4 cups powdered sugar, sifted
12 - 1/4 cup whole milk, more as needed
13 - 2 teaspoons vanilla extract
14 - Pinch of salt
15 - Food coloring, assorted colors, optional

→ Decorating

16 - 1/3 cup rainbow sprinkles

# Directions:

01 - Preheat oven to 350°F. Grease and line a 9x13-inch sheet pan with parchment paper for easy removal.
02 - Whisk flour, granulated sugar, baking powder, and salt together in a large mixing bowl.
03 - In another bowl, whisk whole milk, melted butter, eggs, vanilla extract, and sour cream until fully integrated and smooth.
04 - Gently pour the wet mixture into the dry ingredients, stirring until just combined without overmixing.
05 - Transfer batter to the prepared pan and evenly spread with a spatula.
06 - Bake on the center rack for 28–32 minutes or until a toothpick inserted into the center yields clean results.
07 - Allow the cake to cool completely in the pan set on a wire rack before frosting.
08 - Beat softened butter in a bowl until creamy. Gradually incorporate sifted powdered sugar, then add milk, vanilla extract, and a pinch of salt. Beat until light and fluffy. Divide and tint with food coloring if desired.
09 - Swirl or dollop frosting over the cooled cake, embracing natural imperfection and texture.
10 - Generously scatter rainbow sprinkles over the frosted surface.
11 - Slice directly in the pan and present servings as desired.

# Additional Tips::

01 -
  • Easy to make in one pan with simple ingredients
  • Perfect for any birthday or celebration with customizable decorations
02 -
  • For a chocolate variation, swap 1/2 cup flour for cocoa powder
  • Sour cream can be replaced with Greek yogurt without changing texture
03 -
  • Embrace imperfect swirls for a fun, homemade look
  • Let the cake cool completely before frosting to avoid melted swirls