Set up grill for indirect cooking over medium heat and stabilize temperature at 350°F. Spray 9"x 13" foil pan (metal baking pan) with cooking spray and set aside.
In a small mixing bowl, whisk together the flour, cocoa powder, and salt. In a double-boiler, melt together the chocolate and butter, stirring occasionally. Transfer chocolate to a large mixing bowl and stir in the sugar, eggs, vanilla and peppermint extracts. Stir in the flour mixture until just combined. Spread into prepared pan.
For peppermint patty: Beat together the cream cheese and sugar in a small mixing bowl. Beat in the egg and peppermint extract until combined, and then beat in the flour. Dollop over brownie batter, then swirl in with a knife or spatula.
Place foil pan in a second foil pan for stability and insulation. Place on hot grill away from heat. Cover and grill/bake 20 to 30 minutes, or until a toothpick inserted 2-inches from the edge of the pan come away almost clean. Rotate pan halfway through baking. Remove from grill and cool completely.
For chocolate glaze: melt together the chocolate and butter in a double boiler, stirring until combined. Pour over cooled brownie. Chill in refrigerator until set.
Recipe by Grilling Outdoor Recipes powered by Bull Outdoor Products at https://blog.bullbbq.com/peppermint-patty-brownies/