Preheat your oven to 350°F (175°C) and line a baking pan with parchment paper.

In a saucepan, melt the butter over medium heat until it turns golden brown and smells nutty. Remove from heat and let it cool slightly.

In a mixing bowl, combine the browned butter, brown sugar, and granulated sugar. Mix well.

Add in the eggs and vanilla extract, mixing until combined.

In another bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fold in the chocolate chips.

Spread half of the cookie dough in the prepared pan.

Pour the brownie batter over the cookie layer, spreading it evenly.

Drop spoonfuls of the remaining cookie dough over the brownie batter.

Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.

Let it cool before slicing into bars.