Instructions

• Preheat oven to 350°F (175°C). Butter a 13x9x2-inch metal baking pan.
• In a heavy-bottomed saucepan over low heat, combine 1 1/2 sticks butter and 4 ounces chopped unsweetened chocolate. Stir constantly until melted and smooth. Remove from heat and let cool for 3–5 minutes.
• In a large bowl, whisk together 4 large eggs and 1 3/4 cups sugar until pale yellow and slightly thickened, about 3 minutes.
• Gradually whisk the warm chocolate mixture into the egg-sugar mixture until evenly combined (add slowly so the eggs do not cook).
• Add 3/4 cup all-purpose flour and stir just until incorporated; do not overmix.
• Stir in 1 1/2 teaspoons vanilla extract and 1 cup semi-sweet chocolate chips. Spread the batter evenly in the prepared pan and smooth the top.
• Bake for about 25 minutes, or until the edges are set and a toothpick inserted near the center comes out with a few moist crumbs (not wet batter). Remove from oven.
• Cool the brownies completely in the pan on a wire rack before frosting.
• For the frosting, beat 1/2 cup softened butter with an electric mixer until creamy.
• Gradually add 4 cups powdered sugar, 3 tablespoons green creme de menthe, and 3 tablespoons half-and-half. Beat until smooth; if the frosting is too thick, add the remaining tablespoon of half-and-half and beat until you reach spreadable consistency.
• Stir 1/2 cup mini chocolate chips into the frosting.
• Spread the frosting evenly over the cooled brownies. Slice and serve.