1. Prepare the Cookie Base:

1. Preheat the oven to 350°F (175°C).
2. Grease or line an 8×8-inch baking pan with parchment paper.
3. In a medium bowl, whisk together flour, cocoa powder, baking soda, and salt.
4. In a separate bowl, cream together butter and sugar until light and fluffy (about 3 minutes).
5. Beat in egg and vanilla extract until well combined.
6. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
7. Press the cookie dough into the bottom of the prepared pan, smoothing it out into an even layer.

2. Make the Mint Layer:

1. In a medium bowl, mix powdered sugar, melted butter, and peppermint extract.
2. Add the chopped mint chocolate or mint ice cream and stir until everything is evenly combined.
3. Spread the mint layer over the cookie base, smoothing it out into an even layer.

3. Bake & Cool:

1. Bake the bars for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
2. Let the bars cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

4. Make the Chocolate Glaze:

1. In a small microwave-safe bowl, melt chocolate chips and butter together in the microwave in 30-second intervals, stirring until smooth and fully melted.
2. Once the bars are completely cooled, drizzle the chocolate glaze over the top, spreading it into an even layer.

5. Serve & Enjoy:

1. Let the glaze set for 30 minutes before cutting the bars into squares.
2. Serve chilled or at room temperature and enjoy the delicious minty, chocolatey goodness!