1-First Step: Preheat oven to 350°F and grease an 8×8-inch baking pan with butter or line with parchment for easy removal. This setup prevents sticking and ensures clean cuts later.

2-Second Step: Melt 1/2 cup butter with 4 oz chopped unsweetened chocolate in a microwave-safe bowl. Heat in 30-second bursts, stirring until smooth. Let cool slightly to avoid cooking the eggs.

3-Third Step: Stir in 1 cup sugar, then beat in 2 eggs one at a time. Add 1 tsp vanilla extract, 1/2 cup flour, and 1/4 tsp salt. Mix just until combined for fudgy texture, not overmixed batter.

4-Fourth Step: Pour batter into the prepared pan and spread evenly. Bake 25-30 minutes until a toothpick inserted in the center comes out with moist crumbs. Cool completely on a wire rack, about 1 hour. Rushing this step leads to soggy layers.

5-Fifth Step: Beat 1/2 cup softened butter until creamy, about 2 minutes with an electric mixer. Gradually add 2 cups powdered sugar, alternating with 2 tbsp milk to avoid lumps.

6-Sixth Step: Mix in 1/4 tsp mint extract and a few drops green food coloring. Whip until fluffy and spreadable, 3-4 minutes. Taste and adjust extract for stronger mint if desired.

7-Seventh Step: Spread mint mixture evenly over cooled brownies. Use an offset spatula for smooth edges. Chill in fridge 15-20 minutes to firm up before adding the top layer.

8-Eighth Step: Melt 1 cup chocolate chips with 1/4 cup butter in microwave or double boiler, stirring until glossy. Cool 5 minutes to thicken slightly.

9-Ninth Step: Pour over mint layer, spreading gently to edges. Refrigerate 30-60 minutes until set. This creates the signature crisp snap.

10-Final Step: Lift brownies from pan using parchment overhang. Cut into 16 squares with a sharp knife, wiping between cuts for neat edges. Serve at room temp for best fudgy bite. Store extras as noted below. Pro tip: Warm knife in hot water for ultra-clean slices.