(adapted from Bon Appetit, February 2011)
Nonstick baking spray
1 1/4 cups sugar
3/4 cup natural unsweetened cocoa powder
1/4 teaspoon kosher salt
10 tablespoons unsalted butter, cut in 1-inch pieces
2 teaspoons water
1 teaspoon Tahitian vanilla extract
2 large eggs (straight from the fridge)
1/3 cup plus tablespoon flour
1 cup walnut pieces, toasted
Preheat oven to 325 degrees. Line an 8x8x2-inch metal pan with foil, leaving a 2-inch overhang, and spray the pan with nonstick baking spray.
Combine the sugar, cocoa powder, and salt in a small bowl, and set aside.
Melt butter in a medium saucepan over medium heat, and continue cooking and frequently swirling the pan until butter stops foaming and there are brown bits in the bottom of the pan, about 5 to 8 minutes.
Remove the pan from the heat, and immediately dump in the sugar-cocoa mixture. Add the water and vanilla, and stir to combine.
Let cool 5 minutes, and then add the eggs one at a time, beating vigorously after each addition with a firm rubber spatula or wooden spoon.
Add the flour, and stir until blended. Then beat vigorously for 60 strokes.
Stir in the nuts.
Transfer the batter to the prepared pan, and smooth the top.
Bake brownies until toothpick inserted in center comes out with only moist crumbs attached, about 25 to 30 minutes.
Cool in pan on rack.
Cut into squares, and serve.