Perfect Brownies

Preheat oven to 325u0b0F with rack on the lower-middle level.
Spray 8-inch square baking pan with non-stick spray.
Cut a 16-x-8-inch sheet of foil into the pan and up and over two sides and roll up overhanging sides (you will use this as a handle to remove brownies after they are cooked).
Spray the foil with non-stick spray as well.
In small bowl, stir together the flour, salt and baking powder.
In a medium-sized bowl, melt the chocolate and butter together (you can do this in microwave, or over a pan of simmering water).
After the chocolate is melted, remove from the heat and whisk in the sugar and vanilla.
Whisk in the eggs one at a time.
Continue to stir until the mixture is completely smooth and glossy.
Add the dry ingredients and stir until just incorporated.
Stir in the nuts if you are using them.
Pour the batter into the prepared pan and smooth the top.
Bake until toothpick inserted into the center comes out with wet crums, 35 to 45 minutes (If the toothpick comes out clean, the brownies are overcooked).
Cool the brownies in the pan on a wire rack fo 5 minutes.
Using the foil handles, pull the cooked brownie from the pan and turn it out on the rack upside down, to cool completely, this will take nearly an hour.
Cut the brownies into 16 squares.
(Note: If you are not going to serve immediately, wrap the whole brownie in plastic wrap, then foil and refrigerae for up to 5 days or freeze).