How to Make It
Preheat the oven to 350°. Butter and lightly flour a 9-by-13-inch baking dish. In the top of a double boiler, melt the butter with the chocolate; let cool.
Meanwhile, in a large bowl, beat the eggs with the granulated sugar and brown sugar until thickened; beat in the vanilla. Using a rubber spatula, gently fold in the chocolate mixture until combined. Sift the flour over the batter and fold it in. Fold in the pecans.
Pour the batter into the prepared pan and bake for about 25 minutes, or until a tester inserted in the center comes out with moist crumbs attached. Let the brownies cool in the pan for 1 hour before cutting into squares.