Monster Cookie Bars


With or without ice cream and hot fudge, these Monster Cookie Bars are sure to be a hit! Peanut butter, M&Ms, oatmeal…they’re the trifecta of perfect cookie bar.

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Monster Cookie Bars - this easy bar cookie recipe is full of peanut butter, oats, and tons of M&Ms! EVERYONE loves these, especially with ice cream!

When I was in the throes of toddlerhood, I would never have guessed the challenges of parenting an older kid. Jordan is now 11 (and a half!) and she’s in that weird in-between stage between needy kid and more self-sufficient teenager. She’s also the first (and only) child, so I’ve never crossed any of these parenting situations before. It’s all new to me, which makes me a tad more overprotective and worried than, say, someone whose done it all a few times.

Pretty much daily these days I’m faced with scary decisions: can she stay in the car while I run into Starbucks? Can she stay home alone? Can she walk the dog alone? Is it okay to let her run into the grocery store by herself to buy gum? Every time a situation pops up my stomach clenches in fear and indecision: what do I do?

Last week Mel was out of town so we went to my parent’s house for a few days. It’s a 2-hour drive and neither of us can make it without stopping. We had the dog with us, and it was 105°. For days before we left, the question played through my mind of exactly how to go to the bathroom in this situation. Do I leave them both in the running car (with A/C) while I go into the gas station? Or do I make them get out and stand outside while I do my thing? Should I stop at Taco Bell or the gas station? Mind you, both scenarios have Jordan going into a restroom in a very public place alone.

I seriously wrestled with the decision of what to do for days. I woke up at 4am the day we left having anxiety and almost panic-attacks. You guys, this parenting thing is HARD!

Monster Cookie Bars Recipe

Making and eating cookie bars is way easier than parenting. Let’s just do that, mmkay?

Have you ever had a monster cookie? It’s a peanut butter oatmeal cookie that’s filled with chocolate chips and M&Ms. I love them, because they’re a combination of two of my favorite cookie recipes. But as much as I like cookies, I think I like cookie bars better because there is no scooping. I just press the dough in the pan and bake it, easy peasy.

This recipe starts with my favorite peanut butter cookie recipe. I adapted it to add oats to make it MONSTER. And, of course, I added chocolate chips, regular M&Ms, and PEANUT BUTTER M&M’s. I swear, peanut butter M&M’s are my downfall. I can easily eat a 1 lb. bag all by myself!

Once you bake them they become a soft and gooey cookie bar that’s perfect for when you’re craving peanut butter and oatmeal cookies together.

I had an even better idea and I added ice cream on top…

Monster Cookie Bars - this easy bar cookie recipe is full of peanut butter, oats, and tons of M&Ms! EVERYONE loves these, especially with ice cream!

Ice cream + cookie bars can really fix any parenting problem, don’t you think?

(Oh, and we made there and back, stopping both times, and Jordan didn’t get kidnapped. #ThankGoodness)

Monster Cookie Bars

Monster Cookie Bars - this easy bar cookie recipe is full of peanut butter, oats, and tons of M&Ms! EVERYONE loves these, especially with ice cream!
Total Time 45 minutes
Yield 24 bars
Serving Size


  • 1/2 cup unsalted butter softened
  • 1 cup peanut butter
  • 3/4 cup packed brown sugar
  • 1/2 cup granulated sugar
  • 2 large eggs
  • 1 tablespoon vanilla extract
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon salt
  • 3/4 cup all-purpose flour
  • 3 cups quick cooking oats
  • 1 cup chocolate chips
  • 2 cups M&Ms any kind, I used regular and peanut butter


  • Preheat oven to 350°F. Line a 9x13” pan with foil and spray with nonstick cooking spray.
  • Beat butter and peanut butter with a hand or a stand mixer until smooth. Mix in both sugars until creamy. Add eggs, vanilla, baking soda, and salt and mix until smooth, then slowly mix in the flour and oats. Stir in the chocolate chips and M&Ms.
  • Press cookie dough into the prepared pan. If desired, sprinkle more M&Ms on top for decoration. Bake for 22-25 minutes or just until the edges are golden brown. Cool before cutting into bars.
  • These are great served as bars or as an ice cream sundae! Store in an airtight container for up to 3 days or freeze for up to one month.

Nutritional information not guaranteed to be accurate

Click here to see more PEANUT BUTTER recipes! 

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  1. Looks yummy! I think it shows you’re a good mom that you’re thinking about these things!