In the bowl of a stand mixer with a paddle attachment, mix the softened butter until smooth. Add the sugar and whip until light and fluffy.
Add the peanut butter, combine it, then add the eggs and vanilla, mixing to combine again. Scrape down the sides of the bowl in between new additions.
Add the dry ingredients and mix until incorporated. Then, add the chips and oats. Mix to combine, then gently fold in the M&M candies by hand.
Transfer the mixture to a 9 x 13 pan lined with parchment paper. Spread into an even layer, then bake the cookie bars for 25 minutes. Check on them. They will likely need more time. Cover them with foil and bake them for 10 minutes more or until they are thoroughly baked.
To check if they are done, insert a knife into the center to ensure it is no longer wet. The edges will be golden brown, and the top should be puffy. Allow to cool before cutting the bars. I cut them 6 x 4 to make 24 bars! However, you can cut however many squares you want.
Notes
Nutrition Info:
portion size: 57g
calories: 266
total fat: 14g (saturated fat 6.4g)
cholesterol: 30mg
sodium: 111mg
totals carbs: 32g
fiber: 1.5g
sugars: 22g
protein: 4.3g
calcium: 30mg
iron: 1mg
potassium: 137mg
Keyword cookie bars, M&M cookies, peanut butter cookies