2/3 Cup all-purpose flour
1/4 Teaspoon salt
1/2 Teaspoon baking powder
2 Ounces unsweetened chocolate
4 Ounces bittersweet or semisweet chocolate
1 Stick butter
1 Cup sugar
2 Teaspoons vanilla
3 Large eggs
Adjust oven rack to lower-middle position, and preheat oven to 325 degrees.
Whisk flour, salt, and baking powder in a small bowl, set aside.
Line an 8-inch-square baking pan with a sheet of aluminum foil in the bottom of pan. The foil overhangs both sides of the pan; use as handles to removed baked brownies from pan. Coat foil with cooking spray.
In a medium heat-proof bowl set over a pan of almost simmering water, melt chocolate and butter, stirring occasionally until mixture is smooth. (Alternatively, melt chocolate and butter in microwave oven. Microwave chocolate alone at 50% power for 2 minutes. Stir chocolate; add butter; and continue microwaving at 50% for another 2 minutes, stopping to stir the mixture after 1 minute. If chocolate is not entirely melted, microwave an additional 30 seconds at 50% power.)
Remove melted chocolate mixture from heat; whisk in sugar and vanilla.
Whisk in eggs, one at a time, fully incorporating each before adding the next.
Continue whisking until mixture is completely smooth.
Add dry ingredients; whisk until just incorporated.
Pour batter into prepared pan.
Bake until edges of brownies have puffed slightly, center feels not quite firm when touched, and a toothpick inserted into center comes out with several moist, fudgy crumbs. 50 minutes probably less start at 40 and check them49.
Cool for 5 minutes. Using foil handles, lift brownies out of the pan, allow to cool to room temperature prior to cutting.