# What You Need:
→ Vanilla sheet cake
01 - 2 1/2 cups all-purpose flour
02 - 2 1/2 teaspoons baking powder
03 - 1/2 teaspoon fine salt
04 - 1 cup unsalted butter (2 sticks), room temperature
05 - 2 cups granulated sugar
06 - 4 large eggs, room temperature
07 - 1 tablespoon pure vanilla extract
08 - 1 cup whole milk, room temperature
→ Sage green buttercream
09 - 1 1/2 cups unsalted butter (3 sticks), room temperature
10 - 5 cups powdered (confectioners') sugar, sifted
11 - 2–3 tablespoons heavy cream or whole milk
12 - 2 teaspoons vanilla extract
13 - Pinch of fine salt
14 - Sage green gel food coloring, as needed
→ Gold buttercream accents
15 - 1/2 cup reserved prepared buttercream
16 - Gold edible luster dust
17 - 1 teaspoon clear vanilla extract or vodka (optional, for mixing with luster dust)
# How-To Steps:
01 - Preheat oven to 350°F. Grease a 12×18-inch sheet pan and line with parchment paper, leaving an overhang for easy removal.
02 - Whisk together the all-purpose flour, baking powder and salt in a medium bowl until evenly distributed.
03 - In a large mixing bowl, beat the unsalted butter and granulated sugar on medium speed until pale and light in texture, about 3–4 minutes.
04 - Add the eggs one at a time, mixing well after each addition, then mix in the vanilla extract until homogeneous.
05 - Add the flour mixture to the butter mixture in three additions, alternating with the milk and beginning and ending with flour; mix only until just combined to avoid overworking the batter.
06 - Transfer the batter to the prepared pan, smooth the surface, and bake at 350°F for 28–32 minutes or until a toothpick inserted into the center comes out clean. Cool completely in the pan on a wire rack.
07 - Beat the softened butter in a large bowl until creamy. Gradually add the sifted powdered sugar, then mix in vanilla and a pinch of salt. Add heavy cream or milk 1 tablespoon at a time until the frosting reaches a spreadable consistency.
08 - Tint the majority of the buttercream with sage green gel coloring to achieve an even color; reserve 1/2 cup of plain buttercream for gold accents.
09 - Using an offset spatula, spread the sage green buttercream evenly over the cooled sheet, creating a smooth, level surface.
10 - Mix gold edible luster dust with a few drops of clear vanilla extract or vodka to form a paint, and use a food-safe brush to paint over piped details made with the reserved buttercream. Alternatively, blend luster dust into reserved buttercream for a marbled gold effect.
11 - Add any additional decorative elements such as gold sprinkles or piped graduation motifs. Chill briefly to set the buttercream before slicing into 24 neat squares.
