The only ingredient I didn't have onhand already was the unsweetened chocolate (go figure). So I did a substitution I found in the cookbook, using 3 oz of semisweet instead of the 2 oz of unsweetened chocolate. I also reduced the sugar by 2 tbsp.
Oh, and there was no way I was going to let the brownies cool for 2 HOURS before cutting it.
5 oz bittersweet or semisweet chocolate, chopped
2 oz unsweetened chocolate, chopped
8 tbsp unsalted butter, cut into pieces
3 tbsp Dutch-processed cocoa powder
1_1/4 cups sugar
3 large eggs
2 tsp vanilla extract
1/2 tsp salt
1 cup all-purpose flour
Adjust an oven rack to the middle position and heat the oven to 350 degrees. Line an 8-inch square pan with foil (see notes: Making a foil sling), then lightly coat with vegetable oil spray. Melt the chocolates, butter and cocoa in the microwave, stirring often, 1 to 3 minutes. Let the mixture cool slightly.
Whisk the sugar, eggs, vanilla and salt together in a large bowl until combined, about 15 seconds. Whisk in the melted chocolate mixture until smooth. Stir in the flour until no streaks remain.
Scrape the batter into the prepared pan and smooth the top. Bake until a toothpick inserted into the center comes out with just a few crumbs attached, 35 to 40 minutes.
Let cool completely on a wire rack to room temperature, about 2 hours, before removing the brownies from the pan using the foil and cutting into squares.
Making a foil sling:
Fold two long sheets of aluminum foil so that they are as wide as the baking pan (if the dish is rectangular the two sheets will be different sizes). Lay the sheets of foil in the pan, perpendicular to one another, with the extra hanging over the edges of the pan.
Push the foil flat into the corners and up the sides of the pan. Try to iron out any wrinkles in the foil, laying it flush to the pan. Spray the sides and bottom of the pan with vegetable oil spray before adding the batter.
After the browines are baked and cooled, use the foil sling to transfer them to a cutting board before cutting into squares.