2 four ounce bars semi-sweet chocolate, coarsely chopped
1 cup all-purpose flour
1/3 cup unsweetened cocoa powder
1 teaspoon baking powder
1/4 teaspoon kosher salt
5 Tablespoons unsalted butter, room temperature
3/4 cup packed light brown sugar
1/4 cup granulated sugar
2 large eggs
1 teaspoon pure vanilla extract
1 cup chopped walnuts
1/2 cup semi-sweet chocolate chips