Katharine Hepburn Brownies

INGREDIENTS

• ½ cup unsalted butter, cut into small pieces
• 2 ounces unsweetened chocolate, finely chopped
• 1 cup granulated sugar
• 2 eggs
• 1 teaspoon vanilla extract
• ¼ cup all-purpose flour
• ¼ teaspoon salt
• 1 cup chopped walnuts