Ingredients
1/2 cup (1 stick) unsalted butter, plus more for foil
8 ounces semisweet chocolate, chopped
1 1/4 cups sugar
3/4 teaspoon salt
3 large eggs
3/4 cup all-purpose flour, spooned and leveled
1 cup chopped walnuts or pecans (optional)
Preparation
Preheat oven to 350 degrees. Line bottom and sides of an 8-inch square baking pan with foil; butter foil. Set aside.
Place butter and chocolate in a medium heatproof bowl set over (not in) a saucepan of simmering water; stir frequently, until almost melted. Remove from heat; stir until completely melted.
Whisk in sugar and salt until smooth; whisk in eggs. Gently whisk in flour just until smooth (do not overmix). Fold in nuts, if using.
Spread batter evenly in prepared pan. Bake until a toothpick inserted in center comes out with a few moist crumbs attached (they should form a ball when rolled between your fingers), 45 to 50 minutes. Cool completely in pan.
Use foil to lift brownie cake from pan; peel off and discard. Cut into 16 squares.
