Peanut butter and oatmeal cookies chocked full of chocolate chips and M&M’s, there are so many delicious flavors in these Soft and Chewy Monster Cookies you can’t help but love them.

Close-up image of a Monster Cookie just out of the oven.

These Soft and Chewy Monster Cookies are for people who can’t decide what kind of cookie they want. This recipe throws all the classic cookie ingredients into one mixing bowl. Peanut Butter – check! Oatmeal – check! Chocolate Chips – check! M&M’s – check! These yummy cookies have all the flavors … and that’s a Two Sisters’ “good thing.” Enjoy!

Ingredients you will need

  • Peanut Butter: we like to use Jiffy Peanut Butter (the smooth version) but if you want a little bit of extra crunch go ahead and use your favorite type of peanut butter.
  • Oatmeal: You will want to use Quaker Old Fashioned Oats, we find that the instant/one-minute oatmeal doesn’t work as well in a cookie.
  • Mini Chocolate Chips: We think these Monster Cookies taste best with Mini Chocolate Chips but regular Chocolate Chips will be fine if that is all that you have.
  • M&M’s: Crunchy, chocolately and colorful M&M’s are the fun mix-in that really makes these cookies stand out next to a glass of milk.
Glass mixing bowl filled with the cookie dough for a batch of Monster Cookies.
  1. Mix butter and peanut butter until thoroughly combined.
  2. Add sugar and brown sugar and mix until creamed.
  3. Mix in Eggs and Vanilla until light and fluffy.
  4. Mix in Baking Soda.
  5. Mix in flour, a bit at a time until completely mixed.
  6. Add oatmeal and stir until combined.
  7. Add Mini Chocolate Chips and M&M’s, stir until combined.

Baking Instructions

Collage image showing a ball of Monster Cookie dough on a cookie sheet and a sheet of cookies just out of the oven.
  1. Roll cookie dough into balls and place on a prepared cookie sheet.
  2. Bake in a 350 degree oven for 9-11 minutes.
  3. Allow cookies to cool before storing them.

How to Make Christmas Monster Cookies

This yummy cookie recipe is so easy to turn into a gorgeous Christmas Monster Cookie. All you need is a bag of Red and Green Holiday M&M’s. (Or if you can’t find any of those, pull out the Red and Green M&M’s from a regular bag.) Follow the recipe exactly as directed and then replace the regular M&M’s with the holiday colored versions. So easy! So Christmas-y!

Expert Tips and FAQs

Close up on a stack of Monster Cookies on a white surface.
How should I store the cookies?

These Best Ever Monster Cookes should be stored in an airtight container. They will stay fresh longer if they are completely cool before you pack them up.  We usually add a layer of parchment paper between each row of cookies in our plastic container.

How long will the cookies stay fresh?

These Best Ever Monster Cookes should be stored in an airtight container. They will stay fresh longer if they are completely cool before you pack them up.  We usually add a layer of parchment paper between each row of cookies in our plastic container.

The cookies will be fresh for 2-3 days at room temperature. If you want them to last longer, you should freeze them. They will be fine in the freezer for 2-3 months.

Close up of a Monster Cookie sitting on a wire cooling rack.

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Soft and Chewy Monster Cookies

Soft and Chewy Monster Cookies

Yield 36 cookies
Prep Time 10 minutes
Cook Time 11 minutes
Total Time 21 minutes

Peanut butter and oatmeal cookies chocked full of chocolate chips and M&M's, there are so many delicious flavors in these Soft and Chewy Monster Cookies you can't help but love them.

Ingredients

  • 1/2 cup Butter (Sweet Cream, Salted, Room Temperature)
  • 1/2 cup Peanut Butter
  • 1 cup Granulated Sugar
  • 1 cup Dark Brown Sugar (packed)
  • 3 Eggs
  • 1 tsp. Vanilla
  • 2 1/2 cups All-Purpose Flour
  • 2 cups Old Fashioned Oatmeal
  • 2 tsp. Baking Soda
  • 1  tsp. Salt
  • 3/4 cup M&M's
  • 1 cup Mini Chocolate Chips

Instructions

  1. Mix butter and peanut butter until thoroughly combined.
  2. Add sugar and brown sugar and mix until creamed.
  3. Mix in Eggs and Vanilla until light and fluffy.
  4. Mix in Baking Soda.
  5. Mix in flour, a bit at a time until completely mixed.
  6. Add oatmeal and stir until combined.
  7. Add Mini Chocolate Chips and M&M's, stir until combined.
  8. Roll cookie dough into balls.
  9. Bake in a 350 degree oven for 9-11 minutes.

Notes

These Best Ever Monster Cookes should be stored in an airtight container. They will stay fresh longer if they are completely cool before you pack them up.  We usually add a layer of parchment paper between each row of cookies in our plastic container.

The cookies will be fresh for 2-3 days at room temperature. If you want them to last longer, you should freeze them. They will be fine in the freezer for 2-3 months.

Ingredient Notes:

Peanut Butter: we like to use Jiffy Peanut Butter (the smooth version) but if you want a little bit of extra crunch go ahead and use your favorite type of peanut butter.

Oatmeal: You will want to use Quaker Old Fashioned Oats, we find that the instant/one-minute oatmeal doesn't work as well in a cookie.

Mini Chocolate Chips: We think these Monster Cookies taste best with Mini Chocolate Chips but regular Chocolate Chips will be fine if that is all that you have.

M&M's: Crunchy, chocolately and colorful M&M's are the fun mix-in that really makes these cookies stand out next to a glass of milk.

Did you Make this Recipe? Leave a review below, then snap a picture and tag @twosisterscrafting on Instagram so we can see it!