1. Use an 8 inch skillet for thicker brownies and bake 2 to 5 minutes longer. Do not overbake for a fudgy center and pull when the middle still looks slightly underdone. Swap chocolate chips for chopped dark chocolate or add 1 tsp espresso powder to deepen cocoa flavor. Replace walnuts with pecans or omit nuts for a classic chewy brownie. Store covered at room temperature up to 3 days or refrigerate up to 5 days and warm briefly before serving