Ingredients

7 ounces hazelnuts

1 cup plus 2 tablespoons unsweetened cocoa powder

1 teaspoon salt

3 cups sugar

1 pound (4 sticks) unsalted butter

12 ounces bittersweet chocolate (70 percent), chopped

6 large eggs

1 tablespoon instant coffee dissolved in 1 tablespoon of hot water

Preparation

  1. Prepare Nuts: Oven-toast hazelnuts (15 minutes) until fragrant and the skins blister; transfer to a kitchen towel to cool slightly, then rub off the skins. Let cool completely. Transfer the nuts to a food processor. Add the cocoa, salt and 1/2 cup of the sugar and pulse until finely ground.

Prepare Batter:

  1. Line a 9-by-13-inch baking pan with foil, pressing it into the corners and leaving overhang on the 2 short sides.

  2. In a large saucepan, brown the butter over moderate heat. Remove from the heat and add the chopped chocolate; let stand until melted, about 2 minutes. Whisk the butter and chocolate until smooth. Let cool slightly.

4A. In a large bowl, using an electric mixer, beat the eggs with the remaining 2 1/2 cups of sugar and the coffee until tripled in volume, about 5 minutes. 4B. Beat in the chocolate-butter mixture. 4C. Add the cocoa-hazelnut mixture and beat to combine, scraping down the bowl.

  1. Bake in prepared pan for about 50 minutes, until the top is glossy and a toothpick inserted in the center comes out with a few moist crumbs attached. Let the brownie cool completely on a rack, then refrigerate until chilled.

  2. Lift the brownie out of the pan and peel off the foil. Cut into 20 pieces and serve.