For Garlic Bread Muffins:
Omit the onion. Increase garlic to five cloves and parmesan cheese to 1/2 cup.
For Herb Muffins
Stir 1 tablespoon of dried herbs into the batter. For milder herbs, like basil, consider increasing the amount to 1 1/2 tablespoons. For stronger herbs, like rosemary, reduce amount to 2 teaspoons.
For Caramelized Onion Muffins
Add 1/2 cup cooled caramelized onions to the batter.
For Dairy-Free Muffins
Replace the milk with dairy-free milk and omit cheese. Dairy-free muffins bake off lighter than muffins with dairy.