Make Ahead: These bars can be stored, covered tightly with plastic wrap, on the counter for up to 3 days. You can reheat in the microwave for about 15 seconds before serving, if desired.
Variations: Easily change up these bars with different types of M&M’s, such as white chocolate or peanut butter M&M’s. This is not only a great way to change the flavor, but also to customize the bars for holidays by using the fun holiday-colored candies.