These monster cookies are filled with peanut butter, chocolate chips, oatmeal and M&Ms. This recipe yields cookies that are soft, chewy, full of texture and completely ginormous. Packed with flavor and extra thick – adults love this recipe just as much as children!
**This recipe was updated November 3, 2022 with new photos, recipe tips and a slightly updated recipe**
Monster cookies are what you get when you combine oatmeal cookies, peanut butter cookies, M&M cookies AND chocolate chip cookies. They’re soft and chewy – which gives them a delicious texture – and have the most delicious peanut butter flavor that goes perfectly with the chocolate. You’ll love this recipe because it produces cookies that are thick enough to hold lots of chocolate chips and M&Ms, but still turn out deliciously chewy.
This recipe is also perfect because there’s no need to chill the dough. But you can optionally choose to freeze the dough balls for later.
Monster Cookie Recipe
As mentioned, there are 4 key ingredients in monster cookies: peanut butter oats, M&Ms and chocolate chips.
I’m including step-by-step photos and recipe tips below, but you can always skip ahead and get straight to the recipe card if you’re a cooking baking expert/made these before.
- Start by preheating the oven to350F degrees (180C or 170C on a convection oven). Then line cookie sheets with parchment paper or silicone baking mats. If you plan to freeze the dough, you can obviously skip this step.
- In a large bowl, beat together the butter, brown sugar, granulated sugar and peanut butter. For this recipe, the butter should be softened but not starting to melt. I found that equal amounts of butter and peanut butter produced the best combo of soft and flavorful cookies.
- Then mix in the egg and vanilla extract. Having the egg at room temperature will provide the best results.
- Turn off the mixer and add in the flour, baking powder, baking soda and salt. I recommend doing a few stirs by hand first to avoid the dry ingredients flying everywhere when you turn on the mixer. Then start to beat together until combined.
- Stir in the oats. Note that I recommend using old-fashioned oats (AKA large rolled oats) as opposed to quick oats for this recipe. Quick oats will technically work, but I prefer the texture with large rolled oats.
- Then stir in the chocolate chips and M&Ms. You can definitely use mini or regular for this recipe.
- Form the dough into balls. I recommend using a cookie scoop to avoid your hands getting sticky. I used 2 scoops of a 1.5 tablespoon cookie scoop for 3 tablespoons in size.
- Place the dough 2-3 inches apart on your lined cookie sheets and bake 1 sheet at a time for about 10-12 minutes, or until the tops look set. When the cookies come out of the oven you can place a few extra chocolate chips and/or M&Ms on top for the perfect cookie look.
Note: If you choose to make smaller cookies with about 1.5 tablespoons of dough each, they’ll bake for about 8-10 minutes.
Freezing the Dough
Absolutely. Make the dough and form it into balls. Then pop the dough balls into a freezer bag, remove any excess air, and freeze for up to 2 months. Bake the dough from frozen – they’ll likely take 1-2 extra minutes.
These monster cookies are the best combination of peanut butter, chocolate, and soft, chewy cookie goodness. You’ll love how easy the recipe is, and how incredibly delicious these monster cookies are to eat. So pour yourself a big glass of milk, and get ready for delicious cookie goodness. 
If you love these monster cookies, make sure to try these other favorites:
- Monster Cookie Bars
- M&M Cookies
- Oatmeal Peanut Butter Cookies
- Peanut Butter Chocolate Chip Cookies
- Oatmeal Chocolate Chip Cookies
Soft and Chewy Monster Cookies
Equipment
- Cookie Sheets
Ingredients
- ½ cup unsalted butter (112 grams) softened
- ½ cup brown sugar (100 grams)
- ⅓ cup granulated sugar (66 grams)
- ½ cup peanut butter (130 grams)
- 1 large egg
- 1 teaspoon vanilla extract
- ¾ cup plus 2 tablespoons all-purpose flour (109 grams)
- 1 tablespoon cornstarch AKA cornflour in the UK and Australia
- ½ teaspoon baking soda
- ½ teaspoon baking powder
- ¼ teaspoon salt
- 1 cup old-fashioned oats (90 grams)
- ½ cup chocolate chips (95 grams) plus more for the tops
- ½ cup M&Ms (about 100 grams) plus more for the tops
Instructions
- Preheat the oven to 350F degrees and line 2 cookie sheets with parchment paper or baking mats.
- In a large bowl beat the butter, brown sugar, granulated sugar and peanut butter until smooth.
- Beat in the egg and vanilla extract.
- Turn off the mixer and add in the flour, cornstarch, baking powder, baking soda and salt. Do a few stirs by hand, then beat with the mixer on a low speed until incorporated.
- Mix in the oats.
- Stir in the chocolate chips and M&Ms.
- Form the dough into balls about 3 tablespoons in size (I use a cookie scoop to do this), and place 2-3 inches apart on the lined cookie sheets.
- Bake one cookie sheet at a time in the preheated oven for about 11-13 minutes or until the tops look just set.
- Cool on the tray for at least 10 minutes, then transfer to a wire rack and continue cooling. While the cookies are till warm, optionally place a few extra chocolate chips and/or M&Ms on top of each cookie.
Notes
- Peanut Butter: I always recommend using smooth, commercially prepared peanut butter instead of anything natural, homemade or where the oil sits on top. Because the amount of oil in these types of peanut butter vary, the results will vary.
- Oats: I recommend using large rolled oats (AKA old fashioned oats). Quick oats will work, but I prefer the results with large rolled oats. Do not use steel cut oats (AKA Irish oats) or instant oats.
- M&Ms: Feel free to use regular or mini.
- Storage: Store cookies in an airtight container at room temperature for up to 4 days.
- Nutrition: Details provided are an estimate only and based on 1 cookie assuming the recipe yields 16 equal sized cookies.
Sooooo soft & chewy – exactly how I like my cookies!
My grandkids love this recipe- I double it and add about half a cup of Heath toffee bits. So good.