Grease a 9 x 13 pan and preheat oven to 350 degrees.
Whisk the flour and salt together in a small bowl. Set aside.
Now make a water bath (or use your double boiler). Fill a suacepan with water, about half way. Set it on the stove and heat the water. Place a heat-proof bowl, like a mixing bowl, right on top. The water may touch the bottom of the bowl, but it should not over flow. Place the butter and chocolate in the bowl. We are now melting the butter and the chocolate together.
Stir frequently; chocolate needs to be melted gently so it won’t seize. When the butter and chocolate are combined, add one cup of sugar and the vanilla. Set the mixture aside.
In a bowl for mixing, put the remaining cup of sugar and the eggs. Mix together until just combined.
Take about half of the sugar/egg mixture, and while stirring, add to the chocolate mixture. Keep the egg mixture moving to prevent cooking the eggs.
Now back to your mixer — beat the remaining egg/sugar mixture on medium high until it doubles in volume, or about 3 minutes.
Using your spatula, fold the whipped egg mixture into the chocolate mixture. Now sprinkle the dry ingredients over your batter. Gently fold, working only until you no longer see the flour.
Scrape all that batter into your prepared pan. Bake in a 350-degree oven for about 25 minutes, until done.
The top of the brownie will look like a dry lake bed. Test the brownies to see if they are done. You are mainly looking for the brownies to set up. When it sets up you are done heating them. They will continue to cook when you remove them from the oven. This will ensure that you do not overcook the brownies. You will want them nice and moist.
You MUST resist the urge to cut into these treats. Just wait! Let the brownies set for about an hour. You will be happy you waited.