01 - Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper, allowing slight overhang for easy removal.
02 - Melt butter in a mixing bowl. Whisk in sugar, eggs, and vanilla extract until fully combined and smooth.
03 - Sift cocoa powder, flour, and salt into the wet mixture. Mix until just combined, being careful not to overmix.
04 - Fold in semisweet chocolate chips until evenly distributed. Pour batter into the prepared pan and spread into an even layer.
05 - Bake for 25 to 30 minutes until a toothpick inserted in the center comes out with a few moist crumbs. Cool completely in the pan before proceeding.
06 - Beat softened butter until creamy. Gradually incorporate powdered sugar, milk, peppermint extract, and food coloring if desired. Mix until smooth and spreadable.
07 - Spread the mint mixture evenly over the cooled brownie base. Refrigerate for 20 minutes to set the layer.
08 - Melt chocolate chips and butter together using a microwave or double boiler, stirring constantly until smooth and glossy.
09 - Pour the chocolate ganache over the mint layer and spread evenly. Refrigerate for approximately 30 minutes until completely set.
10 - Cut into 12 equal squares. Serve chilled or bring to room temperature before serving for a softer texture.