Best Brownies

Adapted from a Cooks Illustrated brownie recipe.

1 and 1/2 sticks unsalted butter (6 oz)
6 ounces unsweetened chocolate (I used 100% Unsweetened Guirardelli, black label) (Don't go cheap here, this is the main ingredient!)
2 and 1/4 cups sugar
4 large eggs
1 tablespoon vanilla extract

1 and 1/4 cup all-purpose flour (NOT the self rising kind)
3/4 teaspoons baking powder
1/2 teaspoon kosher salt

1 cup chopped walnuts

9"x13" pan (I used a straight edged aluminum commercial brand)
parchment paper (NOT waxed paper, that melts)

1. Preheat oven to 325F.
2. Cut a piece of parchment paper 9"x13" and place in bottom of the pan. This will help take the brownies out.
3. Optional: Roast the walnuts in the oven for 5 minutes if already chopped, 10 minutes if whole.
4. Chop walnuts after they cool off if not chopped already.
   
5. If you have time, melt butter in a medium saucepan on the stove at low heat. Or, carefully, melt butter on microwave. 2-3 minutes at power 50% will probably do. Make sure you chop the butter in small cubes because butter tends to explode in the microwave when heated.
6. Chop chocolate and put in the melted butter. Let it rest for 5-10 minutes until it is all melted. Mix w/ a spatula. If there are still unmelted chucks, melt on microwave at 30% power using 30 second intervals and mixing in between until all is melted. Do not overheat or the chocolate will burn. It should look nice and smooth and shiny. If it gets gritty you burnt it and it's over.
7. Mix sugar w/ the melted chocolate and butter using a spatula. It will look sort of grainy.
8. Whisk eggs into the mix, one at a time w/ a hand whisk (or even the same spatual will do, it's just harder).
9. Whisk in the vanilla.
10. Sift together the flour, baking powder and salt into the chocolate mixture and mix together w/ the spatula until all of the dry ingredients are incorporated. Do not overmix.
11. Place mix into prepared pan, leveling w/ spatula.
12. Sprinkle chopped nuts evenly over the chocolate mix. You can use the bottom of a measuring cup and lightly press the nuts into the mix, but not too much so that they don't get buried into the mix.
13. Bake for 25-30 minutes at 325F. 25 minutes will yield fudgy brownies, 30 minutes will be more cakey. Over 30 can yield overdone and dry so watch out!
14. Let cool before removing from pan and cutting.
15. Enjoy by themselves or with vanilla or coffee ice cream.