I've been making Monster Cookies since my daughter started grade school, but it took me a couple of years before I discovered a fantastic recipe for them. They're a little crisp at the edges, but chewy in the middle. They're not only delicious - they happen to be gluten-free!
My monster cookies take a ton of peanut butter, which helps them stay chewy. The best thing, though, is that it takes only oats, and no flour! That makes the cookies 100% whole grain, and they can be gluten-free! To counter being too healthy, of course, there's lots of chocolate chips and M&Ms.
I found this recipe for Monster Cookies in a hand-written recipe notebook I started in 2003. I have no idea where I found it, and no memory of ever trying it. Alex pulled it out a few months ago to try it, though, and it's definitely a keeper!
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Ingredients
Here's the ingredients:
- Butter
- Peanut butter
- Brown and granulated sugar
- Corn syrup
- Eggs and vanilla
- Rolled oats and baking soda
- Chocolate chips
- M&Ms (or other candies)
I use regular, creamy, store brand peanut butter. "Natural" peanut butter without additional oil or sugar will not work properly. Crunchy peanut butter may work, but your batter may end up a bit dry.
Light corn syrup is optional but recommended. The cookies will be great on Day 1 with or without corn syrup; however, corn syrup keeps them soft and chewy on Days 2, 3, and beyond. Cookies without corn syrup will feel a bit stale by Day 3 and won't have as chewy a texture. You can use agave syrup or honey instead of corn syrup, but it may slightly change the cookies' flavor.
There's no flour in these cookies! Instead, it's all rolled oats. Both old-fashioned and quick-cooking oats are fine; we don't notice much difference between the two in cookies. Do not use instant oats, which will be mushy, or steel-cut oats, which are too thick and won't cook properly.
Baking soda interacts with the acid in the brown sugar
Monster cookies take both chocolate chips and M&Ms. I often use store-brand semi-sweet chocolate chips. M&Ms are milk chocolate and add contrast; you should be able to use any candy-coated chocolate pieces, though.
Instructions
Use a stand mixer or a large bowl with an electric hand mixer (affiliate link) for this recipe. It makes a ton of cookie dough, and it's hard to beat together the butter and peanut butter by hand.
- Cream the butter, peanut butter, brown sugar, sugar, and corn syrup. Mix on medium speed for 1-2 minutes, until creamy and lightened.
- Scrape the bottom. Add the eggs and vanilla. Mix on low 30 seconds to break them up as they slosh around. Scrape up the bottom, then mix for another 30-60 seconds on medium.
- Scrape up the bottom. Add the oats, and sprinkle the baking soda over them so it doesn't clump up. Stir on low just until mixed.
(Use a rubber spatula to stir them in, if using a handheld mixer.)
- Add the chocolate chips and M&Ms. Stir on low just to combine, or stir in with the spatula.
With oats and no flour, you can't really overmix the dough. Using low speed is just because the dough is thick and the bowl is full.
- Use a medium (1.5-tablespoon or #40) cookie scoop (affiliate link), or two spoons, to scoop dough. Place cookies 2 inches apart on a parchment- or silicone mat (affiliate link)-lined baking sheet.
- Bake for 10-12 minutes, until the cookies are set and look slightly dried. They'll be puffy, and perhaps slightly browned.
Let the cookies cool for 5-10 minutes before removing them from the baking sheet. They'll deflate a little as they cool; this is normal.
Hint: In my oven, 10 minute cookies are a little underdone. 12 minute cookies are a bit less chewy, although they're still not crunchy. 11 minutes is perfect for me; your baking times will vary based on your oven.
Storage
Store the cookies in an air-tight container at room temperature. Cookies are best on the day they're made, and they're still pretty good on the day after. If you've added corn syrup, they'll still be pretty chewy by day 3. (I've never had any leftover after that!)
There's no wrong way to serve the cookies. They're only made from oats - that makes them breakfast, right? They're a hearty snack, and I recommend a cold glass of milk to go along with them, if that's your thing.
Make Ahead Prep
Since this recipe makes enough dough for 60 cookies, I usually bake one or two trays of these, and then save the rest of the cookie dough for another day, as I do with the majority of my cookies. The dough freezes well, and then you have cookies whenever you want!
Line a plate or a baking sheet with waxed paper or plastic wrap; this will help you pry the frozen balls of dough off later.
Scoop the cookie dough onto the lined sheet. Crowd the balls of dough as close as you can without them actually touching. Place the tray in the freezer, and leave them there until frozen.
Label a freezer bag with the date and baking instructions. Then pry the dough from the sheet and place them in the bag, squeezing out as much air as possible. (I often forget to put them in a freezer bag for a few days!)
Whenever you want cookies, just heat your oven to 350F. Don't thaw the cookies first - just put them on the baking sheet and bake them from frozen! You'll add a minute or two to the baking time.
Recipe FAQ
There's two types of "natural" peanut butter. One is peanut butter made from just peanuts, without additional oil or sugar. It does not work in baking unless you make adjustments to the sugar and fat in the recipe.
The other kind of "natural" peanut butter is conventional peanut butter made with sugar and oil, except that it uses palm oil. This kind of peanut butter should work in the recipe since it has additional fat and sugar. However, I dislike it for two reasons. First, the palm oil industry is a major contributor to deforestation, etc., since it largely doesn't use sustainable farming techniques. Second, as a user, I find that the oil separates and I have to stir it back into the rest of the peanut butter.
Oats are naturally gluten-free, but are cross-contaminated since they are usually processed on the same equipment as flour. If you need to avoid gluten, choose oats that are certified gluten-free.
I personally prefer average-sized cookies, because I can eat more of them than I can giant cookies. To make giant or "monster" monster cookies, use a ¼ cup to measure the dough. Bake for a few minutes extra, until the tops look dried and set.
Line a plate or a baking sheet with waxed paper or plastic wrap; this helps you pry off the frozen balls of dough. Scoop the cookie dough onto the lined sheet. Crowd the balls of dough as close as you can without them actually touching. Place the tray in the freezer, and leave them there until frozen solid. Once frozen, place in a freezer-safe zipper bag. Bake cookies directly from frozen, adding 2 minutes to the baking time.
More Peanut Butter and Chocolate Treats
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📖 Recipe
Monster Cookies
Equipment
- electric mixer
- medium (#40) cookie scoop
- silicone mats or parchment paper
Ingredients
- 8 tablespoons butter (113 grams; softened)
- 1 ½ cups peanut butter (384 grams)
- 1 ¼ cup brown sugar (250 grams)
- 1 cup granulated sugar (200 grams)
- 1 ½ teaspoon corn syrup (10 grams; optional but recommended)
- 3 eggs (~150 grams)
- 1 ½ teaspoon vanilla extract (7 grams)
- 4 ½ cups rolled oats (360 grams; old-fashioned or quick are both fine)
- 2 teaspoons baking soda
- 1 cup chocolate chips (170 grams/6 ounces)
- 1 cup M&Ms (212 grams/7.5 ounces)
Instructions
- With a stand mixer or hand mixer (affiliate link), combine butter, peanut butter, sugars, and corn syrup. Mix at medium speed for 1-2 minutes, until mixture has lightened in color.
- Scrape the bottom, and then add vanilla and eggs. Mix again on medium speed for about 1 minute, until everything is combined. Scrape the bottom again to look for unmixed bits.
- Add in the oats and the baking soda. (Switch to a rubber spatula if you were using a hand mixer (affiliate link).) Stir on low until everything is mixed in, pausing to scrape the bottom as you go.
- Add the chocolate chips and M&Ms. Stir on low just to combine.
- Using a medium, 1 ½ tablespoon (or #40) cookie scoop, or two spoons, portion dough onto parchment or silicone-lined baking sheets, leaving 2 inches between cookies.
- Bake at 350F for 10-12 minutes. (11 is perfect in my oven, but yours may be different.) The tops will look set and dry, and they will be slightly browned and a little puffy on top, though they will deflate as they cool.
- Cool for 5-10 minutes before removing from the baking sheets.
Freezer Instructions/Make-Ahead
- Scoop the cookie dough onto plates or cookie sheets lined with waxed paper or plastic wrap. Crowd them on as closely as possible, without letting them touch.
- Freeze dough until solid. Remove the balls of cookie dough and store them in a labeled freezer bag.
- To bake, heat your oven to 350F. Place balls of cookie dough 2 inches apart on your parchment-lined sheets. Bake, from frozen, for 12-14 minutes.
Notes
[Originally written May 24, 2022. Recipe restructured and lightly revised August 28, 2025.]
Leona Konkel says
This recipe is one of our family favorites. I love that it makes so many, because I restock my stash of freezer cookie dough every time I make it. I hope you love it too. Let me know how it turns out!