stick unsalted Butter, cut into tablespoons, plus more for pan
oz. bittersweet chocolate, preferably 70% cocoa, chopped (about 1.25 cups)
Cup granulated Sugar
Cup packed light brown Sugar
large Eggs, room temperature
Cup unsweetened Cocoa powder
tsp coarse Salt
Preheat oven to 350` Lightly brush an 8 inch square baking pan with butter. Line with parchment, leaving a slight overhang on 2 sides. Butter parchment. Place butter and chocolate in a large heatproof bowl set over a saucepan of simmering water and melt, stirring, until smooth. Remove from heat and whisk in sugars. Whisk in eggs, 1 at a time, until combined. Whisk in cocoa and salt, then fold in flour until combined. Pour batter into pan and bake until a toothpick inserted in center comes out with moist crumbs, about 35 minutes. Let cool completely in pan on a wire rack. Lift out brownies with parchment overhang. Cut into 16 squares.