1 stick (1/2 cup) plus 3 tablespoons unsalted butter, softened
2 cup sugar
4 large eggs, lightly beaten
1 teaspoon vanilla
1/4 teaspoon salt
1 cup flour
8 ounce bittersweet chocolate, broken with the tip of a knife into large chips
4 ounce white chocolate, broken with the tip of a knife into large chips
1 and 1/4 cups chopped pecans
1/4 cup cacao nibs (optional)
confectioners' sugar
Directions
Step 1: Heat oven to 350 F. Line the inside of a 13-by-9-inch metal baking pan with heavy-duty foil. Lightly grease the foil.
Step 2: Into a large, heavy-bottomed saucepan, add 8 ounces of chopped, unsweetened chocolate and 1 stick (1/2 cup) plus 3 tablespoons of softened, unsalted butter. Melt over very low heat, stirring constantly with a wooden spoon, until smooth. Remove from heat.
Step 3: Stir in 2 cups of sugar until incorporated. Next, stir in 4 large eggs (lightly beaten), 1 teaspoon vanilla and 1/4 teaspoon salt. Stir in 1 cup of flour just until incorporated. Gently fold in 8 ounces of chopped bittersweet chocolate, 4 ounces of white chocolate chips, 1 and 1/4 cups chopped pecans and 1/4 cup cacao nibs (optional).
Step 4: Spread the batter in the prepared pan. Bake until center is just set, but not at all dry, about 27 to 30 minutes. Cool completely in the pan on a wire rack. (Refrigerate for easier cutting if you wish.)
Step 5: To cut, lift the brownies out of pan. Invert onto a cutting board and gently peel off the foil. With a large knife, cut into small squares. Serve sprinkled with powdered sugar.