Melt the butter and 1 cup of semi-sweet chocolate in a large bowl. I like to use a large glass bowl and microwave it in 30 second intervals, stirring in between, until fully melted and smooth.

Add the granulated sugar and brown sugar to the melted chocolate mixture and whisk until incorporated.

Add the eggs one at a time, whisking well after each addition.

Add the vanilla extract and whisk to combine.

Sift together the flour, cocoa powder, and salt in a medium bowl. Add to the batter and whisk until incorporated.

Fold in the remaining 1 cup of chocolate chips with a spatula.

Pour ⅔ of the brownie batter into the prepared pan and spread evenly. I like a thicker layer of brownie as a base. Spoon the dulce de leche over the batter and gently spread it out, leaving a little border around the edges so it stays inside the brownies while baking.

Top with the remaining brownie batter and carefully spread it over the dulce de leche layer.

Sprinkle the extra chocolate chips on top.

Bake in the pre-heated oven for about 42 to 50 minutes, depending on your pan and oven, until the edges are set and the center no longer looks raw. A toothpick inserted into the brownie part should come out with moist crumbs attached, but not wet batter.

Let the brownies cool completely before slicing for cleaner layers.