Soft-Baked M&M Cookie Bars

I made a few different kinds of cookies for Christmas this year and I've been trying to figure out if I should make any more or not. I had a bag of red and green mini M&Ms but have never really loved the cookie recipe that is on the bag, so I wasn't sure what to make with them. Usually I would make a skillet cookie but that is a better dessert to take to a small gathering where you will cut and serve it there (like after having dinner at someone's house). I saw this Soft-Baked M&M Cookie Bars recipe and decided to give it a try because it looked easy and I could cut them up and bring them to my sons' Preschool Christmas party on a tray, and freeze any remaining bars.

This recipe is super simple to make and takes no time at all. I love recipes that don't require a mixer and use melted butter (rather than having to plan ahead to soften butter).

I only used mini M&Ms in this recipe - I did not add chocolate chips. One 11-ounce bag of mini M&Ms was not quite 2 cups, so it was the perfect amount. I mixed most of them into the dough but reserved a few which I put on top before baking the bars in the oven.

Do not let these bars over-bake! Mine were a bit overdone when I checked them at 25 minutes the second time I made them (for Easter), so next time hopefully I'll remember to check them earlier.

If you use parchment paper and let the bars cool for an hour, it is very easy to lift them out of the pan and cut them up. I cut all 4 edges off and then cut the rest into little bars.

These are delicious and come together so quickly - give them a try the next time you have M&Ms that you aren't quite sure what to do with!

Soft-Baked M&M Cookie Bars

Recipe courtesy “Sally’s Baking Addiction” Website

 

Think of these bars as no-chilling, no-rolling EASY M&M cookies! Using melted butter, more brown sugar than white sugar, and a touch of cornstarch guarantee the absolute softest, chewiest M&M cookie bar texture.

2¾ cups all-purpose flour

1½ teaspoons cornstarch

1 teaspoon baking soda

½ teaspoon salt

1 cup (2 sticks) unsalted butter, melted & cooled for just 5 minutes*

1 cup packed light or dark brown sugar

½ cup granulated sugar

2 large eggs, at room temperature

2 teaspoons pure vanilla extract

1¼ cups mini or regular-size M&Ms

¾ cup semi-sweet chocolate chips

 

Preheat the oven to 350°. Adjust oven rack to the center rack position. Line the bottom and sides of a 9×13-inch baking pan with parchment paper, leaving an overhang on the sides to easily lift the bars out of the pan. Set aside.

 

Whisk the flour, cornstarch, baking soda, and salt together in a large bowl. Set aside.

 

In a medium bowl, whisk the melted butter, brown sugar, and granulated sugar together until no brown sugar lumps remain. Whisk in the eggs and vanilla extract. Pour this into the flour mixture and mix together with a large spoon or rubber spatula. The dough will be very soft, slick, and thick. Fold in the M&Ms and chocolate chips. The M&Ms and chips may not stick to the dough because of the melted butter, but do your best to combine them.

 

Transfer dough to the prepared baking pan and press/smooth into an even layer. Bake for 26–30 minutes or until lightly browned on the sides and top and a toothpick inserted in the center comes out mostly clean with a few moist (not wet) crumbs. Do not over-bake. If you notice the bars browning too much before 25 minutes, tent the pan with foil. Bars puff up in the oven, but settle as they cool.

 

Allow the bars to cool in the pan set on a wire rack for at least an hour. While they’re still warm, I like to press a few more M&Ms and chocolate chips into the tops, just for looks (optional!). Once relatively cool, lift the bars out of the pan using the overhang on the sides and cut into squares.

 

Cover leftover bars and store at room temperature for up to 1 week.

 

NOTES:

Make Ahead & Freezing Instructions: You can make the cookie dough and chill it in the refrigerator for up to 3 days or freeze for up to 3 months. Allow to come to room temperature and continue with step 4. Baked cookie bars freeze well for up to 3 months. Thaw bars overnight in the refrigerator and bring to room temperature before serving.

 

Cornstarch: If you don’t have cornstarch, you can leave it out. The cookie bars will still be soft.

 

Butter: Avoid letting the melted butter cool for too long, otherwise your dough will be crumbly instead of soft (and your cookie bars can end up cakey). You want it still warm, but not hot enough to begin cooking the eggs.

 

M&Ms: You can use regular-size, mini, or a mix of both. I like to crush some of them, too, to sprinkle on the top before baking. Totally optional!

 

Do I have to add chocolate chips? You can skip the chocolate chips. If you skip them, increase M&Ms to 1½ cups. You could also replace the chocolate chips with white chocolate chips, butterscotch chips, or peanut butter chips.

Edit April 2023: I made these again with regular size M&Ms for Easter. I prefer baking with the mini M&Ms and wish they made them more often in seasonal colors. I've only ever seen them in Christmas colors and in Red, White & Blue over the summer. These were slightly over-baked so next time I will be sure to set my timer for less than 25 minutes and check them earlier.