Prep 20 mins - Cook 55 mins - 16 PieceIngredients:1/2 cup (1 stick) unsalted butter, plus more for baking pan1 cup all-purpose flour (spooned and leveled)1/3 cup unsweetened cocoa powder1/2 teaspoon baking powder1/2 teaspoon fine salt1 1/4 cups sugar1/2 pound bittersweet chocolate chips (1 1/2 cups)3 large eggs1 teaspoon pure vanilla extract32 miniature c