In a medium bowl whisk together the brownie mix, 1 egg, 1/3 cup vegetable oil, and 2 tbsp water until a soft dough forms. Spread dough onto a lightly greased 12" pizza pan. (use a pan that does not have holes in the bottom). Bake for 15-18 minutes or until toothpick just barely comes out clean from center. Don't over bake!
Whip the butter in your mixer with a whisk attachment until light and fluffy. Add the peppermint extract and heavy cream. Gradually add the powdered sugar, beating in-between additions. Add more cream for a thinner frosting, or more powdered sugar for a thicker frosting.
Spread frosting on top of FULLY COOLED brownie pizza. Sprinkle with chopped candy cane kisses, then drizzle with chocolate syrup if desired. Cut into slices and enjoy!