August 21, 2022

Peanut Butter Monster Cookies

Traditional monster cookies are a “Frankenstein” mixture of an oatmeal cookie, peanut butter cookie, and chocolate chip cookie all in one. This monster cookie recipe, however, is focused on all things peanut butter. If you love peanut butter then this cookie is for you!

This easy recipe can be mixed in one large bowl and does not contain any flour. The cookies are more like a peanut butter cookie with oats and they are fantastic! They are soft and chewy with flavor packed into every bite.

Recipe source: Family recipe passed down from Grandma Ruth.

Peanut Butter Monster Cookies

Soft and chewy cookies with peanut butter in every bite!


Anne Voss

  • 3 eggs, room temperature
  • 1 teaspoon vanilla extract
  • 1 cup granulated sugar (200g)
  • 1 1/2 cup light brown sugar, packed (226g)
  • 1 stick of butter, softened to room temperature (113g)
  • 1 teaspoon light corn syrup
  • 2 teaspoons baking soda
  • 1 1/2 cup creamy peanut butter (340g)
  • 4 1/2 cups quick oatmeal (450g or 1 16oz container)
  • 3/4 cup Reese’s peanut butter chips (113g)
  • 2/3 cup Reese’s Pieces mini candy (130g)
  1. Preheat the oven to 350°F.
  2. In a large bowl, mix together eggs, vanilla, sugars, and butter.
  3. Add corn syrup, baking soda, and peanut butter. Mix to combine.
  4. Add oatmeal, peanut butter chips, and Reese's Pieces. Mix well until all ingredients are incorporated and evenly distributed.
  5. Scoop large teaspoons of dough onto a cookie sheet (2 inches apart).
  6. Flatten the dough balls slightly using the back of a spoon or your fingertips.
  7. Bake cookies for 12 minutes. Do not overbake. Cookies will be chewy.
  8. Leave cookies on the cookie sheet for ~3 minutes before transferring them to a cooling rack.

Makes 5 dozen cookies

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Recipe Notes

Below you will find tips and tricks to help achieve the best results possible!


Peanut butter – use creamy peanut butter for this recipe. It is easier to mix and incorporate into the cookie dough.

Oatmeal - make sure you use quick oats for this recipe. Quick oats give the cookies the perfect texture and cook in a short amount of time. Do not use steel-cut oatmeal or old-fashioned oats in this recipe.  

Peanut Butter chips – peanut butter chips look like chocolate chip morsels, except they are peanut butter. I have not seen many off-brands of peanut butter chips and I use the Resse’s brand that you can find in the baking aisle of your grocery store.

Reese’s Pieces – also in the baking aisle you will find mini Reese’s pieces candy. I prefer the mini version for baking, but you can use the full-size candy if you can’t find the minis.

raw cookie dough on baking tray ready to be baked

Supplies Needed

Large mixing bowl. I use a 5-quart mixing bowl.

Cookie sheet lined with parchment paper

Other needed supplies include measuring spoons and measuring cups or a kitchen scale.

stack of monster cookies with a glass of milk in the background

Tips and Tricks

A kitchen scale is your friend when making this recipe. I highly recommend you get one. They are fairly inexpensive and a very helpful tool to have. I got my Taylor scale at Costco, but there are many other brands online. It especially makes measuring peanut butter much easier. No need to deal with the mess of using a measuring cup.

You can drop the cookie dough with a teaspoon or use a cookie scoop. For this recipe, I used a #50 cookie scoop.

These cookies freeze well and I freeze them often. Freeze in an airtight plastic storage bag and then take them out when you need a treat. Or you can save time by making them ahead of a party or event and freeze the cookies until needed.

milk being poured into a short glass and then cookie being dipped in milk


If you prefer more traditional monster cookies, you can use chocolate chips and M&M candy instead of peanut butter mix-ins.

You can also experiment with different baking chips and candy combinations.

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