Chocolate-Mint Brownie Tart

Preparation Preheat oven to 350°F. Unfold crust into 9-inch-diameter tart pan with removable bottom. Fold overhang in and press firmly to sides. Using fingertips, press sides up to form raised edge * inch above pan sides. Pierce crust all over with fork. Freeze 5 minutes. Bake crust until golden, about 22 minutes. Cool. Maintain oven temperature. Melt butter in heavy small saucepan over low heat; pour into large bowl. Add brownie mix, 5 tablespoons plus 1 teaspoon water, egg and peppermint extract; whisk to blend. Stir in packet of chocolate chips, if included in brownie mix. Spoon batter into crust. Bake until tester inserted into center comes out with some moist crumbs still attached, about 45 minutes. Let stand on rack while preparing chocolate toppings. Whisk 3/4 cup semisweet chips and 2 tablespoons plus 2 teaspoons water in heavy small saucepan over low heat until melted and smooth. Remove from heat. Combine white baking chips with 1 tablespoon plus 1 teaspoon water in another heavy small saucepan. Whisk over low heat until melted and smooth. Remove from heat. Spoon melted semisweet chocolate by tablespoonfuls onto warm brownie in 7 or 8 pools, spacing evenly. Spoon melted white chips into remaining spaces to cover brownie. Using tip of knife, swirl chocolates. Let cool at room temperature in pan on rack until top is set, about 2 hours. (Can be made 1 day ahead. Cover; let stand at room temperature.) Remove tart pan sides. Garnish with mint.

Preparation Preheat oven to 350°F. Unfold crust into 9-inch-diameter tart pan with removable bottom. Fold overhang in and press firmly to sides. Using fingertips, press sides up to form raised edge * inch above pan sides. Pierce crust all over with fork. Freeze 5 minutes. Bake crust until golden, about 22 minutes. Cool. Maintain oven temperature. Melt butter in heavy small saucepan over low heat; pour into large bowl. Add brownie mix, 5 tablespoons plus 1 teaspoon water, egg and peppermint extract; whisk to blend. Stir in packet of chocolate chips, if included in brownie mix. Spoon batter into crust. Bake until tester inserted into center comes out with some moist crumbs still attached, about 45 minutes. Let stand on rack while preparing chocolate toppings. Whisk 3/4 cup semisweet chips and 2 tablespoons plus 2 teaspoons water in heavy small saucepan over low heat until melted and smooth. Remove from heat. Combine white baking chips with 1 tablespoon plus 1 teaspoon water in another heavy small saucepan. Whisk over low heat until melted and smooth. Remove from heat. Spoon melted semisweet chocolate by tablespoonfuls onto warm brownie in 7 or 8 pools, spacing evenly. Spoon melted white chips into remaining spaces to cover brownie. Using tip of knife, swirl chocolates. Let cool at room temperature in pan on rack until top is set, about 2 hours. (Can be made 1 day ahead. Cover; let stand at room temperature.) Remove tart pan sides. Garnish with mint.