I love these basic bars. The majority of the ingredients I almost always have on hand, and the type of M&M can be switched out with your favorite kind. I like the combo of Peanut Butter M&M's the best.
I made these a while back and everyone loved them.
Thick and Chewy M&M Cookie Bars
Adapted from lizzygoesdutch.blogspot.com and melskitchencafe.com
2 1/8 cups flour
1/2 tsp salt
1/2 tsp baking soda
12 TB butter (1 1/2 sticks), melted and cooled slightly
1 cup brown sugar
1/2 cup white sugar
1 large egg
1 large egg yolk
2 tsp vanilla extract
1 12oz bag Peanut Butter M&M's, divided
1. Preheat the oven to 325 degrees. Adjust the oven rack to lower-middle
position. Line a 9X13-inch baking pan with foil, letting the excess
hang over the edges of the pan by about 1 inch so you can grab those
edges and pull the bars from the pan after they have baked. Spray the
foil-lined pan with nonstick cooking spray.
2. Mix the flour, salt, and baking soda together in medium bowl; set
aside. Whisk the melted butter and sugars in a large bowl until
combined. Add the egg, egg yolk, and vanilla and mix well. Using a
rubber spatula, fold the dry ingredients into the egg mixture until just
combined; do not over mix. Fold in 1 cup of M&M's and turn the
batter into the prepared pan, smoothing the top with the spatula.
Sprinkle remaining M&M's on top and press in slightly.
3. Bake until the top of the bars is light golden brown, slightly firm
to the touch, and edges start pulling away from sides of pan, 24-28
minutes. Cool on a wire rack to room temperature. Remove the bars from
the pan by lifting the foil overhang and transfer them to a cutting
board. Cut into squares and serve.