These are probably the BEST brownies I have ever made
2 sticks (1/2 pound) unsalted butter
8 ounces + 6 ounces semisweet chocolate chips (for Ghiradelli large chocolate chips, that is 1 1/3 cups + 1 cup)
3 ounces unsweetened chocolate, finely chopped (I use Baker’s, sold at grocery stores)
3 extra-large eggs
1 1/2 tablespoons instant espresso powder (okay to omit but it helps to boost the chocolate flavor)
1 tbsp. vanilla extract
1 cup + 2 tbsp. granulated sugar
1/2 cup + 2 tbsp. unbleached all-purpose flour (set aside 1-2 tbsp.)
1/2 tbsp. baking powder
1/2 tsp. kosher salt
1 1/2 cups walnuts, chopped (optional)
Preheat oven to 350 degrees F. Grease and flour a 9 x 13 inch pan.
Melt the butter, 8 ounces of chocolate chips, and unsweetened chocolate on top of a double boiler (I just place a glass bowl atop a saucepan of simmering water, not allowing the bowl to touch the water). Allow the melted chocolate to cool slightly.
Stir together the eggs, espresso powder, vanilla, and sugar. Add the slightly cooled melted chocolate and stir; allow to cool to room temperature.
Whisk together flour, baking powder, and salt. Add to cooled chocolate.
Toss the walnuts and 6 ounces of chocolate chips with 2 tbsp. flour until coated (helps prevent them from sinking to bottom of batter). If using only chips, toss with 1 tbsp. flour. Stir into batter.
Pour batter into prepared pan. Bake for 30 minutes at 350 degrees F or until toothpick inserted in center comes out clean. Cool thoroughly, refrigerate for several hours, then cut into squares. Don’t skip the refrigeration step; it helps the brownies set.