1. Preheat the oven to 350°F and line an 8×8-inch baking pan with parchment paper.

2. In a large bowl, whisk together the melted butter and granulated sugar until glossy.

3. Add the eggs and vanilla extract, then whisk until smooth.

4. Stir in the cocoa powder, flour, and salt just until combined.

5. Spread a little more than half of the brownie batter into the prepared pan.

6. Bake the first layer for 10 to 12 minutes until lightly set.

7. In another bowl, mix the chopped Mint Aero chocolate, sweetened condensed milk, peppermint extract, and green food coloring until creamy.

8. Spread the mint filling evenly over the partially baked brownie layer.

9. Spoon the remaining brownie batter over the top and gently spread it out.

10. Bake for 18 to 22 minutes, until the edges are set and the center is no longer wet.

11. Cool completely, then chill for 1 hour before slicing into squares.