8 tablespoons unsalted butter
4 ounces unsweetened chocolate
1 1/4 cups sugar
1 teaspoon vanilla extract
1/4 teaspoon salt
1/2 cup all-purpose flour
2/3 cup lightly toasted walnuts or pecans (optional)
Preheat oven to 400 degrees. Line an 8-inch-square metal baking pan with foil. In top of a double boiler set over barely simmering water, or on low power in a microwave, melt butter and chocolate together. Stir often, and remove from heat when a few lumps remain. Stir until smooth.
Stir in sugar, vanilla and salt. Stir in eggs one at a time, followed by flour. Stir until very smooth, about 1 minute, until mixture pulls away from sides of bowl. Add nuts, if using. Scrape batter into prepared pan and bake 20 minutes.
Meanwhile, prepare a water bath: Pour ice water into a large roasting pan or kitchen sink to a depth of about 1 inch. Remove pan from oven and place in water bath, being careful not to splash water on brownies. Let cool completely, then lift out and cut into 1-inch squares or wrap in foil.
A few reader tips:
Substituting 1/4-1/2 cup of the sugar with brown sugar adds extra flavor, and I second sprinkling sea salt on top. A tablesspoon or so of bourbon or espresso is also great to add. Finally, the quality of the chocolate used makes a big difference!
I further intensified the flavor with a teaspoon of ground espresso and a cup of bittersweet chocolate chips.
Cut sugar to 1 cup.
Increase walnuts to 1 cup.
Use one of those aluminum “to go” pans as an insert and remove it and put it in the ice bath.