2 oz. unsweetened chocolate, coarsely chopped
1/2 (1 stick) cup unsalted butter, cut into pieces
1 cup white sugar
1/2 teaspoon vanilla extract
1/4 cup all-purpose flour
1/4 tsp. salt
1 cup chopped walnuts or pecans (optional)
1. Preheat the oven to 325 degrees F.
2. Butter and flour an 8-inch baking pan.
3. Melt unsweetened chocolate and butter over very low heat in a heatproof bowl set over a saucepan of about 1 1/2 inches of simmering water, whisking until smooth.
4. Remove from heat and stir in sugar, eggs and vanilla.
5. Whisk in the flour and salt, until well blended.
6. Stir in the nuts.
7. Spread the batter in the baking pan. Bake for 30 to 40 minutes. Remove the pan to a rack to cool completely. Cut into 9 brownies.