Makes 20 2 ½-inch square brownies

1 pound (4 sticks) unsalted butter, plus more to grease pan
1 ½ cups semisweet chocolate chips; or 9 ounces good-quality dark chocolate, broken into pieces
2 cups sugar
8 large eggs
1 teaspoon vanilla extract
2 cups unbleached all-purpose flour
¼ teaspoon salt
2 cups walnuts, very coarsely chopped, or broken up with your fingers

  1. Position your oven racks so that one is in the center, and preheat the oven to 350 degrees. Smear a 13-by-9 inch baking pan with butter.
  2. Melt the 4 sticks butter and chocolate together in a heavy-bottomed saucepan over low heat. Stir frequently with a wooden spoon or heat-proof spatula in a figure-eight motion to prevent the chocolate from sticking and burning. Even slightly burned chocolate will give the brownies a bitter taste.
  3. When the butter and chocolate are combined, add the sugar and cook, stirring constantly, for 2 more minutes. Don’t worry if the chocolate appears grainy; the sugar won’t dissolve completely, but this doesn’t mean you will end up with grainy-textured brownies. Remove the pot from the heat and scrape the chocolate mixture into a big bowl using a heat-proof rubber spatula.
  4. Allow the chocolate mixture to cool for 5-10 minutes before adding the eggs; otherwise, the heat of the chocolate will cook the eggs, and you’ll end up with little scrambled bits of egg in your brownie batter. Whisk in the eggs one at a time, then whisk in the vanilla.
  5. In a separate, medium-size bowl, stir the flour and salt together to mix. Dump the flour into the bowl with the chocolate, and stir until almost no flour remains visible. Stir in the walnuts.
  6. Pour the batter into your prepared baking pan. Place the baking pan on the center rack in the oven, and bake the brownies for 40-45 minutes. We undercook these slightly, which is what makes them fudgy and moist. So a fork inserted in the middle will not come out clean. To test for doneness, open the oven and shake the pan; if the batter jiggles, it needs more time.
  7. Remove the pan from the oven, and place it on a wire rack. Let the brownies cool to room temperature before cutting them into 2 ½-inch squares.