You’ll love these if you’re a big fan of the thin chocolate mint Girl Scout cookies. The dense base layer is like a rich, fudgy brownie, so don’t overcook it or the dessert bars will be dry. Refrigerating the mint bars allows the chocolaty top layer to set properly. You can make the dessert up to one day ahead. For a more grown-up taste, you can also use dark chocolate chips for some or all of the semisweet chocolate chips in the glaze.
1. Preheat oven to 350°.
2. To prepare bottom layer, weigh or lightly spoon flour into a measuring cup; level with a knife. Combine flour and salt; stir with a whisk. Combine granulated sugar, egg substitute, ¼ cup melted butter, 2 tablespoons water, vanilla, eggs, and chocolate syrup in a medium bowl; stir until smooth. Add flour mixture to chocolate mixture, stirring until blended. Pour batter into a 13 x 9 inch metal baking pan coated with cooking spray. Bake at 350° for 23 minutes or until a wooden pick inserted in center comes out almost clean. Cool completely in pan on a wire rack.
3. To prepare mint layer, combine powdered sugar, ¼ cup melted butter, and next 3 ingredients (through food coloring) in a medium bowl; beat with a mixer until smooth. Spread mint mixture over cooled cake.
4. To prepare glaze, combine chocolate chips and 3 tablespoons butter in a medium microwave-safe bowl. Microwave at HIGH 1 minute or until melted, stirring after 30 seconds. Let stand 2 minutes. Spread chocolate mixture evenly over top. Cover and refrigerate until ready to serve. Cut into 20 pieces.