Need an easy dessert recipe to serve a crowd? These Chocolate Chip M&M Cookie Bars are perfect for any party! Just mix, bake, slice and done!
Preheat oven to 350 degrees and prepare a 9X13 pan by lightly greasing it or lining it with parchment paper.
In a large bowl, combine butter (make sure it's not super hot or it will cook the eggs), brown sugar and sugar. Then add eggs, egg yolk and vanilla extract.
In a separate bowl whisk together flour, cornstarch, baking powder and salt.
Add the dry ingredients to the wet and just before it's all combined add in your chocolate chips and M&M's. Stir and then dump into your prepared pan and spread out evenly.
Bake for 25-30 minutes or until the edges start to turn golden brown. Let cool for 5-10 minutes and then serve warm or completely cooled.