Chocolate Chubbies

Name: Chocolate Chubbies
Ingredients: 8 tablespoons (1 stick) unsalted butter, cut into 1/2-inch cubes; 9 ounces semisweet or bittersweet chocolate (no more than 62 percent cacao), finely chopped; 3 ounces unsweetened chocolate, finely chopped; 1/2 cup unbleached all-purpose flour; 1/2 teaspoon baking powder; 1/4 teaspoon fine sea salt; 3 large eggs, at room temperature; 1 1/4 cups superfine sugar; 2 teaspoons pure vanilla extract; 2 cups (12 ounces) semisweet chocolate chips; 1 1/2 cups (5 1/2 ounces) coarsely chopped pecans; 1 1/4 cups (4 1/2 ounces) coarsely chopped walnuts