You can top each muffin like a pizza with your favorite toppings, such as nitrate-free pepperoni, sautéed spinach, chopped fresh basil, or chopped olives. Or you can stir these toppings into the batter before baking. Allow the muffins to cool completely before wrapping and freezing. If you will use them within 2 weeks, place them in glass containers or freezer bags. If you'd like them to last up to 3 months without freezer burn, wrap each one individually in aluminum foil and place them in a resealable freezer bag. Don't forget to label what is in the bag and the date! Thaw frozen muffins at room temperature for about an hour.