Graduation Sheet Cake Buttercream (Printer-friendly)

Moist vanilla sheet cake topped with smooth buttercream and decorated with colorful piped roses.

# What You'll Need:

→ Sheet Cake

01 - 3 cups all-purpose flour
02 - 2.5 teaspoons baking powder
03 - 0.5 teaspoon baking soda
04 - 0.5 teaspoon salt
05 - 1 cup unsalted butter, softened to room temperature
06 - 2 cups granulated sugar
07 - 4 large eggs, room temperature
08 - 1 tablespoon vanilla extract
09 - 1.25 cups whole milk, room temperature

→ Buttercream Frosting

10 - 1.5 cups unsalted butter, softened to room temperature
11 - 6 cups powdered sugar, sifted
12 - 0.25 cup whole milk
13 - 2 teaspoons vanilla extract
14 - Gel food coloring in assorted colors for roses and leaves

# How-To Steps:

01 - Preheat oven to 350°F. Grease and line a 12x18-inch sheet cake pan with parchment paper, ensuring even coverage on all sides.
02 - In a medium mixing bowl, whisk together flour, baking powder, baking soda, and salt until thoroughly combined and aerated.
03 - In a large mixing bowl, beat softened butter and granulated sugar together for 3-4 minutes until the mixture becomes light, fluffy, and pale in color.
04 - Add eggs individually to the butter mixture, beating well after each addition to ensure proper emulsification. Mix in vanilla extract until fully combined.
05 - Alternately add portions of the flour mixture and milk to the creamed mixture, beginning and ending with the flour mixture. Mix on low speed just until combined, avoiding overmixing.
06 - Pour batter evenly into the prepared pan and smooth the top surface with an offset spatula. Bake for 30-35 minutes until a toothpick inserted in the center emerges clean.
07 - Allow cake to cool completely in the pan on a wire rack before proceeding with frosting application.
08 - Beat softened butter until creamy. Gradually add sifted powdered sugar while mixing. Add milk and vanilla extract, then continue beating for approximately 5 minutes until the frosting is smooth and fluffy.
09 - Divide the buttercream into separate bowls. Tint portions with gel food coloring to create colors for roses (red, pink, yellow) and leaves (green), while reserving white buttercream for the base layer.
10 - Spread a thin, even layer of white buttercream across the entire cooled cake to create a smooth foundation for decorative piping.
11 - Fit piping bags with appropriate tips such as petal tips for roses and leaf tips for foliage. Pipe roses and decorative leaves strategically across the cake surface, concentrating designs on corners or as a border arrangement.
12 - Using a small round piping tip, pipe a graduation congratulations message or personalized text directly onto the frosted cake surface.

# Expert Tips:

01 -
  • It feeds a crowd without making you feel like you're stuck in the kitchen for hours.
  • The buttercream roses are easier than they look, and people always think you hired a professional baker.
  • You can make it the day before and just add the piped details on celebration day, which takes pressure off the morning of.
02 -
  • If your buttercream looks grainy or breaks when you're beating it, it usually means the butter was too cold when you started—let it sit another few minutes and beat again.
  • Piping bags should be filled only halfway, or you'll have frosting exploding out the top while you work, which I learned the messy way.
  • The cake actually tastes better the next day once the flavors settle, so make it a day ahead if you can manage it.
03 -
  • Measure your ingredients by weight if you have a kitchen scale, because it's more accurate than volume measurements and takes the guesswork out of flour density.
  • If you're worried about your piping skills, practice the roses on a small piece of parchment paper held taut against the cake—mistakes are hidden, confidence is real.
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