# What You'll Need:
→ Vanilla sheet cake batter
01 - All-purpose flour — 2 1/2 cups
02 - Baking powder — 2 1/2 teaspoons
03 - Salt — 1/2 teaspoon
04 - Unsalted butter, room temperature — 1 cup (2 sticks)
05 - Granulated sugar — 2 cups
06 - Large eggs, room temperature — 4
07 - Pure vanilla extract — 1 tablespoon
08 - Whole milk, room temperature — 1 cup
→ Sage green buttercream
09 - Unsalted butter, room temperature — 1 1/2 cups (3 sticks)
10 - Powdered sugar (confectioners' sugar), sifted — 5 cups
11 - Heavy cream or whole milk — 2 to 3 tablespoons
12 - Vanilla extract — 2 teaspoons
13 - Salt — a pinch
14 - Sage green gel food coloring — as needed to tint
→ Gold buttercream accents
15 - Reserved prepared buttercream — 1/2 cup
16 - Edible gold luster dust — as needed
17 - Clear vanilla extract or vodka (to mix with luster dust), optional — 1 teaspoon
# How to Make It:
01 - Preheat oven to 350°F. Grease a 12×18-inch sheet pan and line the bottom with parchment, leaving an overhang for easy lift-out.
02 - Whisk together the flour, baking powder, and salt in a medium bowl until evenly distributed.
03 - Using an electric mixer, beat the room-temperature butter and granulated sugar on medium speed until light and fluffy, about 3 to 4 minutes.
04 - Add eggs one at a time, mixing well after each addition, then beat in the vanilla extract until combined.
05 - Add the dry mixture to the butter mixture in three additions, alternating with the milk and beginning and ending with the flour; mix just until combined without overworking.
06 - Pour the batter into the prepared pan and smooth the surface. Bake 28 to 32 minutes, or until a toothpick inserted into the center comes out clean.
07 - Allow the cake to cool completely in the pan on a wire rack before applying buttercream to prevent melting and sliding.
08 - Beat the butter until creamy, then gradually add the sifted powdered sugar. Mix in vanilla and salt, adding 1 tablespoon of cream at a time until the frosting reaches a spreadable consistency.
09 - Tint the majority of the buttercream with sage green gel coloring to the desired shade, and reserve 1/2 cup of plain buttercream for gold accents.
10 - Use an offset spatula to spread the sage green buttercream evenly over the cooled sheet, smoothing the surface and cleaning the edges.
11 - Combine edible gold luster dust with a few drops of clear vanilla extract or vodka to form a paint, or blend the dust into reserved buttercream for a marbled metallic effect.
12 - Pipe details with the reserved buttercream, then brush or paint gold over piped areas or apply gold-marbled buttercream where desired. Finish with sprinkles or graduation motifs as preferred.
13 - Chill the sheet briefly to set decorations, then slice into 24 squares for serving. For the cleanest slices, chill the cake before cutting.
