Step 1

Preheat oven to 350 degrees F. Line an 8-inch square baking dish with aluminum foil, leaving enough to extend over sides, then coat foil with cooking spray. Pour batter into baking dish and bake 35 to 38 minutes or until a toothpick inserted in center comes out with a few moist crumbs on it.  Let cool completely.

Step 2

Remove brownies by lifting the foil from baking dish. Peel off foil and place brownies on a work surface; cut into three rows.

Step 3

Cut off a triangle from one end and cut 4 additional Christmas tree-shaped pieces from each row. (The two end pieces from each row will be odd-shaped triangles, so go ahead and save those for the kids to nibble on.) Press a pretzel stick into the bottom of each ‘brownie tree,” as shown.

Step 4

In a medium bowl, combine the vanilla frosting, confectioners' sugar, peppermint extract, and food color; mix well. Spoon frosting into a pastry bag with a writing tip on it, or into a plastic storage bag with the tip of one corner snipped. Decorate each brownie tree in a zig-zag design, as shown. Decorate with nonpareils or candies.