1 cup unsalted butter
3 ounces unsweetened chocolate, chopped
1 cup granulated sugar
3 large eggs
1 tablespoon vanilla extract
3/4 cup all-purpose flour
1 1/2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon kosher salt
11/2 cup chopped nuts, toasted (optional)* recipe without nuts- see tips below
Preheat oven to 350°. Place rack in bottom third of oven. Line a 9″x 13″ baking pan with foil* or parchment paper. Grease lightly.
Melt butter, half of the chocolate chips, and unsweetened chocolate in a double boiler (or microwave). Let mixture cool to warm.
Whisk sugar, eggs, and vanilla just until mixed. Over-mixing will cause crumbly brownies. Fold in warm chocolate mixture.
Place flour, baking powder, baking soda, salt and remaining chocolate chips into chocolate mixture all at once. Fold dry ingredients into chocolate mixture, then fold in chopped nuts just until combined.
Pour batter into prepared pan. Spread to an even thickness. Place the pan into the oven.