Brown the Butter: In a medium saucepan over medium heat, melt the unsalted butter completely, stirring gently until it bubbles and turns golden brown, about 5-7 minutes. Remove from heat and cool slightly.

Melt the Chocolate: Add high-quality dark chocolate to the warm browned butter, stirring until smooth, about 2-3 minutes. Set aside to cool.

Whisk Sugars and Eggs: In a large bowl, combine granulated and brown sugars with eggs. Whisk until thoroughly blended and the sugar has dissolved, about 5-7 minutes.

Combine Ingredients: Stir the brown butter and chocolate mixture into the sugar-egg mixture. Add vanilla extract, cocoa powder, and salt, mixing until uniform.

Add Flour and Chocolate Chunks: Sift in flour and fold gently until no dry flour remains. The batter should be thick and gooey.

Bake: Preheat oven to 350°F (175°C). Pour batter into a lined or greased 8x8-inch pan. Bake for 25-30 minutes until the top is crackly.

Cool and Slice: Cool brownies in the pan for 30-40 minutes before slicing into squares.