Preheat oven to 350°F and line an 8-inch square metal baking pan with parchment paper.
Whisk together flour, unsweetened cocoa powder, and salt in a medium bowl.
Place chopped chocolate in a medium bowl. Cook butter in a heavy saucepan over medium heat, stirring constantly until it foams, turns clear, and then turns a medium brown, about 5 minutes. Pour brown butter over chocolate and let stand for 1 minute, then stir until chocolate is completely melted and mixture is smooth.
Gradually add C&H® Organic Raw Cane Sugar and C&H® Light Brown Sugar, whisking until smooth.
Whisk in eggs and egg yolk one at a time, until combined. Whisk in vanilla. Add flour mixture and fold in just until no streaks remain. Fold in chocolate chips.
Pour batter into prepared pan and smooth the top. Gently tap pan once to remove air bubbles.
Bake brownies for 25 to 28 minutes, until the top is set and a toothpick inserted in the center comes out with a few crumbs attached. Remove from oven and place on a wire rack to cool completely.
Lift parchment and place brownies on a cutting board. Cut into squares with a sharp knife. Store leftover brownies in an airtight container at room temperature.