For the Brownie Base:

1. 1. Preheat your oven to 350°F (175°C). Line an 8×8-inch baking dish with parchment paper.
2. 2. In a medium saucepan over low heat, melt the butter gently. Once melted, remove from heat and stir in granulated sugar until well combined.
3. 3. Add eggs one at a time, mixing thoroughly after each addition.
4. 4. Sift together cocoa powder and flour into your butter mixture. Stir until just combined—avoid overmixing to keep them fudgy.
5. 5. Stir in peppermint extract and half of the chocolate chips into the brownie batter.
6. 6. Pour the batter into your prepared pan and spread it evenly. Sprinkle remaining chocolate chips on top. Bake for about 25-30 minutes or until a toothpick inserted in the center comes out mostly clean.
7. 7. Allow brownies to cool completely before cutting into squares.