Ingredients

  • 5 tablespoons unsalted butter, cut in pieces
  • 4 ounces bittersweet chocolate, coarsely chopped
  • 2 ounces unsweetened baking chocolate, coarsely chopped
  • 34 cup sugar
  • 2 large eggs
  • 1 teaspoon vanilla extract
  • 12 teaspoon instant espresso powder, but really good (optional)
  • 14 teaspoon salt
  • 13 cup flour
  • 1 cup chopped walnuts

Method

  • Heat oven to 325 degrees.
  • Line an 8-inch square baking pan with foil; butter the foil.
  • Microwave the butter and chocolate in a medium bowl, stirring every 10 seconds, until melted and blended.
  • Cool slightly; then, with a whisk, stir in sugar (mixture will become grainy).
  • Whisk in eggs, one at a time.
  • Whisk in vanilla.
  • Gently stir in espresso, salt and flour just until blended.
  • With a rubber spatula, fold in walnuts.
  • Scrape batter into prepared pan; smooth top.
  • Bake 30-35 minutes until top is dull and a wooden pick inserted in center comes out with moist, chocolate-streaked crumbs attached.
  • Cool in pan on wire rack.
  • Invert on rack, peel off foil and invert onto a cutting board.
  • Cut into 16 squares.