1. Preheat the oven to 350°F and line a 9×9-inch baking pan with parchment paper. Lightly grease the parchment.

2. In a large bowl, whisk melted butter, granulated sugar, and brown sugar until smooth.

3. Add eggs and vanilla extract, then whisk until glossy and fully combined.

4. Sift in cocoa powder, flour, and salt. Fold gently until the batter comes together.

5. Stir in semi-sweet chocolate chips.

6. Spread half of the brownie batter into the prepared pan.

7. Arrange 8 Kit Kat bars over the batter in an even layer.

8. Spoon the remaining brownie batter over the Kit Kats and smooth the top gently.

9. Bake for 32 to 38 minutes, or until the edges are set and the center has moist crumbs.

10. Let the brownies cool completely in the pan.

11. Melt milk chocolate chips with heavy cream until smooth, then spread over the cooled brownies.

12. Chop the remaining Kit Kat bars and sprinkle them over the top with wafer crumbs.

13. Chill for 30 minutes before slicing into squares.