What do you add to jiffy blueberry muffin mix?

To enhance Jiffy blueberry muffin mix, you typically add one egg, milk, and melted butter or oil as per the package instructions. For extra flavor, consider adding fresh or frozen blueberries, a sprinkle of cinnamon, or a splash of vanilla extract. You can also adjust the sweetness by adding sugar if desired. Just mix the ingredients until combined, then bake according to the directions.