Peanut butter oatmeal cookies packed with m&ms and chocolate chips. These monster cookies are incredibly soft, chewy, thick, and so easy to make!
Have you ever tried a Monster Cookie? If you’ve never had one before, then I think you’re in for a real treat. Monster cookies are peanut butter oatmeal cookies packed with semi-sweet chocolate chips and m&ms. In other words, they’re one of the best oatmeal cookies you’ll ever try, especially if you love peanut butter.
I’ve been wanting to create an easy recipe for Monster Cookies for quite some time now and I figured with Halloween in just a few weeks, it was finally time. These cookies are a perfect way to use up any leftover candy that you may have lying around and they would also be delicious with some Reese’s pieces mixed in.
Another great thing about this recipe is that there’s no dough chilling required. Yes, you read that right! You all know how much I love to chill cookie dough so that cookies bake up thicker, but I found there was no need for that in this recipe. These monster cookies bake up nice and thick and only take about 30 minutes from start to finish.
To create these cookies I worked off of my peanut butter cookie recipe. I reduced the amount of flour because I knew I wanted to incorporate some old-fashioned rolled oats into these cookies. I mean, you can’t have a good oatmeal cookie recipe without a hefty dose of oats. Right?
To make these cookies you’ll be using some basic dry ingredients like all-purpose flour, baking soda, and salt. Remember my post about how to measure your flour correctly? Be sure to stir your flour around to aerate it, gently spoon it into your measuring cup, and then level it off with the back of a knife. Scooping your flour out of the container can cause you to end up with too much flour in your recipe and cookies that don’t spread at all.
I love a thicker cookie, but we want a little spread in these cookies. So be sure to measure your flour correctly when you’re preparing your dry ingredients.
Then, you’ll cream together some unsalted butter, brown sugar, and granulated sugar. Once the butter and sugar are well combined, you’ll mix in some creamy peanut butter, an egg, and a little vanilla extract.
For the peanut butter in this recipe, I like to use a creamy peanut butter like Jif. Just be sure to avoid using a natural peanut butter where the oil separates because it could cause your cookies to spread quite a bit.
You’ll also need some old-fashioned rolled oats for these cookies. I sometimes get questions about substituting quick oats for the rolled oats, but I don’t suggest it. Quick oats are pressed thinner and don’t have the same chewy texture that rolled oats provide in a good oatmeal cookie. I suggest sticking with old-fashioned rolled oats in any oatmeal cookie recipe, including these Monster Cookies.
You’ll also need some m&ms and chocolate chips for these cookies. I like to just buy two small bags of m&ms, the regular size that you can buy as you checkout at the grocery store are perfect.
As I mentioned earlier, these would also be wonderful with some Reese’s pieces mixed into them. I’m thinking another batch may be in order just to try that out now!
Soft and Chewy Monster Cookies
- 1 cup (125 grams) all-purpose flour, spooned & leveled
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 1/2 cup (115 grams) unsalted butter, softened
- 3/4 cup (150 grams) brown sugar
- 1/4 cup (50 grams) granulated sugar
- 1/2 cup (125 grams) creamy peanut butter
- 1 large egg room temperature
- 1 teaspoon pure vanilla extract
- 1 and 1/4 cups (125 grams) old-fashioned rolled oats
- 3/4 cup (150 grams) m&m's
- 1/2 cup (95 grams) semi-sweet chocolate chips
Preheat oven to 350°F. Line two large baking sheets with parchment paper or silicone baking mats and set aside.
In a large mixing bowl, whisk together the flour, baking soda, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using an electric mixer, cream together the butter, brown sugar, and granulated sugar for about 1-2 minutes or until well combined. Mix in the peanut butter, egg, and vanilla extract until fully combined, making sure to stop and scrape down the sides of the bowl as needed.
Slowly mix in the dry ingredients until just combined, then mix in the oats. Add the m&ms and chocolate chips and gently fold them into the cookie dough.
Using a two tablespoon cookie scoop, scoop balls of cookie dough onto the prepared baking sheets, making sure to leave a little room between each one.
Bake in separate batches at 350°F for 10-12 minutes or until the tops of the cookies are set. Remove from the oven and allow to cool on the baking sheet for 5-10 minutes, then transfer to a wire rack to finish cooling.
Store cookies in an airtight container on the counter for up to 1 week.
Love oatmeal cookies? Be sure to try my Oatmeal Raisin Cookies next!