Rose Levy Beranbaum's Best Bittersweet Brownies

4 ounces European bittersweet chocolate, finely chopped
8 tablespoons (1 stick) unsalted butter, cut into pieces
1/2 cup granulated sugar
2 large eggs, at room temperature
1/2 teaspoon vanilla extract
1/4 cup all-purpose flour
Pinch of salt
2 ounces pecans, coarsely chopped (about 1/2 cup)
Position a rack in the center of the oven and preheat to 350
degrees. Line the bottom of an 8-inch baking pan with wax paper.
Lightly butter and flour the inside of the pan, tapping out
excess flour.

In the top part of a double boiler, over hot, not simmering
water, melt chocolate and butter, stirring often, until smooth.
Remove from heat and let stand 10 minutes, until tepid. Whisk in
sugar. One at a time, whisk in eggs, then vanilla. Using a
wooden spoon, stir in flour and salt, just until blended. Stir
in pecans.

Spread batter evenly into prepared pan and bake 20 to 25 minutes,
until a toothpick inserted 1 inch from the side of the pan comes
out with a moist crumb. (The center will appear quite wet.)
Cool for 20 minutes on a wire rack. Run a knife around the
inside edge of the pan to release the brownie from sides, and
invert brownie onto a lightly buttered baking sheet. Carefully
peel off wax paper, invert again onto wire cake rack, and cool
completely. Using a sharp knife, cut into 16 squares. Wrap each
brownie tightly in plastic wrap.