Few kids can pass up a chance to bake a batch of brownies, and this Best Fudge Brownies recipe is especially irresistible. Made with generous measures of chocolate, butter, and sugar, it yields the fudgiest bars we've sampled yet.
Cut the butter into 1/2-inch pieces and place them in the top of a double boiler in which the water is barely simmering. (No Double Boiler? No Problem. The trick is to find a heatproof bowl that fits about halfway inside one of your medium-size saucepans. A glass bowl or a metal mixing bowl with a handle works well. Be sure to fill the pan with only 1 or 2 inches of water - your bowl should always rest above the water, never in it.)
As the butter melts, sprinkle the chocolate evenly into it. Leave the mixture over the heat for 5 minutes, then stir or whisk it until smooth. Transfer the top of the double boiler to a cooling rack and let the chocolate cool to room temperature.
Meanwhile, heat the oven to 350º. Lightly butter a 9- by 9-inch square cake pan (do not use a smaller pan) and dust it with flour, knocking out the excess.
Combine the sugars in a large mixing bowl, using your fingers to break up any lumps. Add the eggs. Beat the eggs and sugar until well blended - about 30 seconds - with an electric mixer set on medium-high speed. Blend in the vanilla extract. Add the cooled chocolate (which should still be liquid) and mix on medium speed just until evenly blended.
Sift the flour and salt into a medium bowl, then stir them into the chocolate mixture, about half at a time, until no streaks of flour remain. Stir in the nuts. Then scrape the batter into the prepared pan and smooth it with a spoon.
Bake the brownies on the center oven rack for 30 to 35 minutes. When done, the brownies will have risen slightly and the top will have a thin, brittle crust. Do not overbake. For the best results, use 3 toothpicks to test for doneness. Insert one into the brownies about 1 inch from the side; it should come out clean. A second toothpick inserted 2 inches from the side should have a little batter stuck to it, and a third, inserted in the center, should be coated with a bit more batter than that.
Transfer the pan to a wire rack and cool the brownies thoroughly. To get the cleanest cuts, cover and refrigerate the brownies for several hours before slicing (provided you can resist that long). Serve slightly cool or at room temperature. Makes 12 to 16 brownies.