Bake the Brownies:
Preheat oven according to brownie mix instructions (usually 175°C / 350°F).
Grease or line a round baking pan (20–23 cm / 8–9 inch diameter).
Prepare the brownie mix following package instructions.
Pour the batter into the pan and smooth the top.
Bake for 25–30 minutes, or until a toothpick inserted comes out with a few moist crumbs.
Cool completely in the pan on a wire rack.
Make the Frosting:
In a large bowl, beat the butter and sifted powdered sugar together until light and fluffy (2–3 minutes).
Add the cold cream cheese and beat until smooth and creamy. Do not overmix.
Divide the frosting into three bowls:
One portion stays white. (just 3 tbsp)
Add green food coloring to one bowl for the Christmas tree.
Add red food coloring to another for Santa’s hat.
Assemble & Decorate:
Once the brownie has cooled, remove it from the pan.
Slice it into 8 wedges (like a pizza).
Pick two triangles to decorate:
Christmas Tree: Pipe the green frosting in a zigzag pattern using a star or round tip. Decorate with sprinkles to mimic lights.
Santa Hat: Pipe the red frosting over the triangle. Then use white frosting to pipe the base and a small pom-pom at the tip of the hat.
Serve and enjoy!