Step 1

Line a 9 x 9-inch baking pan with parchment paper allowing the ends to extend over two of the sides and set aside. Preheat the oven to 350 degrees Fahrenheit and position an oven rack at the top of the oven.

Step 3

Melt the condensed milk and butter together in a medium saucepan over medium heat, stirring frequently. Once the butter has melted, remove from the heat and stir in the chocolate chips. Continue stirring until all of the chocolate chips have melted. Allow the chocolate mixture to cool slightly to avoid scrambling the eggs.

Step 5

In a large bowl, using an electric mixer beat the brown sugar, sugar, eggs, and egg yolk on medium-high speed until lightened in color, about 3 minutes. Beat in the vanilla extract. Stir in the cooled chocolate mixture with a rubber spatula.

Step 7

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

Step 9

Pour the batter into the prepared baking dish. Bake for 45-50 minutes or until a toothpick inserted into the center comes out with very moist crumbs clinging to it. Remember the brownies will continue to bake as they cool.

Step 11

Cool completely before using the parchment paper to lift the brownies from the pan and cutting.