Learn how to make the best gluten-free monster cookies! They’re made with creamy peanut butter, hearty oat flour & oats, and are studded with m&ms and chocolate chips for decadence. You’ll love every bite of these healthy oatmeal cookies!

A pile of gluten free monster cookies arranged on a cooling rack. A small bowl of m&m's are in the top corner next to the cookies.

Say hello to the most delicious monster cookie you’ve ever met! These thick and chewy oatmeal cookies are loaded with peanut butter flavor, and sprinkled throughout each bite are thick m&m candies and chocolate chips.

One of the best things about these cookies is they’re made with quick oats and oat flour (ground up oats), and are naturally sweetened with coconut sugar. All around, you’ll find the ingredients to be pretty healthy, making indulging in them that much sweeter. ❤️

What are Monster Cookies?

I know you’re probably wondering, what makes them “monster” like. This kind of cookie consists of oatmeal, m&m’s, peanut butter, and chocolate chips.

Since they’re a mash-up of different baking ingredients they’re referred to as a Frankenstein/monster cookie – hence the name. You learn something new every day. 😏

Step by Step Recipe Instructions

Preheat oven to 350F

1

Cream together wet ingredients! In a large bowl, mix the peanut butter, melted butter, sugar, vanilla, and egg together.
2

Add dry ingredients! In the same bowl with the wet ingredients, add flour, oats, baking soda, and salt.

A rubber spatula stirring wet ingredients for monster cookies in a ceramic bowl on a dark background.

Oat flour being added to wet ingredients for monster cookies in a ceramic bowl on a dark background.

3

Fold in the chocolate – Gently fold in m&m’s and chocolate chips. Then cover with plastic wrap and chill the dough in the freezer for 10 minutes or refrigerate for 30 minutes.
4

Measure dough and bake! Roll into dough balls (about 2 tablespoons worth of dough per ball) and arrange on a pan lined with parchment paper. Lightly press down on dough balls to help spread. Bake at 350F for 9 minutes then let cool for 10 minutes before enjoying.

Tips for Success & Recipe FAQs

A Healthier M&M to Use!

For this recipe you can of course use regular m&m's. But I prefer using these Unreal chocolate gems because they taste just like m&m's but are made without artificial sweeteners or preservatives. We love baking with them or keeping them in the house for a sweet treat!

Buy Now →

If you click this link and make a purchase, we may earn a commission at no additional cost to you.

Use quick oats over rolled oats: quick oats are easier for baking because they’re smaller pieces and form a better shape. You can also chop up regular rolled oats to replace them.

Flour options: I used oat flour because of its nutritional value. But you can also use a gluten-free flour blend too!

Properly measure the flour – if the flour isn’t accurately measured you run the risk of the cookies being overly stiff and dry if you use too much. Use too little flour and you run the risk of the cookie batter being too wet. To get accurate measurements, I recommend fluffing the flour while you scoop it into the measuring cup then leveling the top off with a butter knife. Or use a spoon to scoop the flour into the measuring cup, and then level off the top.

Always use room temperature ingredients for baking – make sure the egg and melted butter have both been set to room temperature before combining together, otherwise, if the egg is still cold it will solidify the melted butter. And if the butter is too warm, it can slightly cook the egg, which is no Bueno.

What is oat flour?

It’s ground-up whole oats! Simple as that. So, the cookies are full of all the nutritious benefits of oatmeal, while still tasting decadent and delicious. Oat flour can be found at your local grocery store, but if you can’t find it, you can easily make it yourself! See below for details on how to do that.

Can I make my oat flour?

Yes! It’s the easiest to make. Simply blend whole oats or quick oats in a food processor or blender until the consistency is fine like flour. Easy peasy! Store leftover flour in an airtight container or ziplock back.

How to Store Leftovers or Freeze

Keep leftovers fresh: I prefer keeping cookies in an airtight container or ziplock bag and chilling the fridge for up to 7 days. Room temperature also works but chilling gives a great chewy texture and keeps them fresh longer.

Freezing tips: Place cooled cookies in a freezer ziplock bag or airtight container and freeze for 2 to 3 months.

More Gluten-Free Cookies to Try

We are avid cookie bakers and eaters. If you love this kinda cookie recipe, we think you’ll love our gluten-free peanut butter cookies, chewy almond butter cookies, or our 1-bowl chocolate brownie cookies. We have many more cookies to try as well – click here for more sweet eats!