- Preheat oven to 350F with a rack in the middle position. Line a 9“ x 13” x 2“ anodized aluminum baking pan with foil (overhang to make it easy to remove brownies). Grease foil lightly with oil or pam 
- In sauce pan, melt butter over medium-low heat. When fully melted, increase to medium and simmer. Stir constantly, scraping the bottom, until silent and light golden brown. Remove from heat and stir in chocolate 
- In stand mixer with whisk attachment, combine sugars, salt, eggs, and vanilla. Whip on medium-high until extremely thick and fluffy (~8 min, but use visual cues as primary guide) 
- In a separate bowl, sift flour and cocoa powder 
- Reduce mixer speed to low, pour in chocolate-butter mixture 
- Pour cocoa-flour into mixer all at once and continue mixing until roughly combined. Finish by folding edges and bottom with a baking spatula 
- Pour mixture into foil-lined baking pan and bake until internal temperature is 205F (~30 min) 
- Cool completely and then slice into ~24 squares. Store in airtight container