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Monster Cookies

Monster Cookies are chewy, flavorful and completely irresistible. One of our favorites to fill the cookie jar, these peanut butter oatmeal cookies are loaded with chocolate chips and Reese’s Pieces. 

Make this recipe into Halloween Monster Cookies by adding in candy eyeball sprinkles for a fun homemade treat. If you love our Peanut Butter Oatmeal Cookies, give you are sure enjoy this recipe. 

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Monster cookies stacked with reese's pieces candies.

We have a constant flow of family coming through and I try to always have homemade cookies filling the cookie jar. These Monster Cookies are always a hit and our grandkids went crazy for eyeball sprinkles. 

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Ingredients for Monster Cookies.

🟢 Ingredients Needed

  • butter
  • brown sugar
  • peanut butter ~ crunchy or creamy
  • egg
  • vanilla extract
  • all purpose flour
  • old fashioned oats
  • baking soda
  • kosher salt
  • semi-sweet chocolate chips
  • Reese’s Pieces candies
  • candy eyeball sprinkles – optional

Closeup of tray of monster cookies with Reese's Pieces.

🟢 Step by Step DirectionsCollage making peanut butter oatmeal cookie dough.

  1. In a mixer bowl, beat the butter and brown sugar together about 2 minutes.
  2. Add eggs, peanut butter and vanilla. Mix until well combined.
  3. Next, add the flour, oats, baking soda and salt. Mix thoroughly.Collage adding chocolate chips to peanut butter cookie dough.
  4. Add the chocolate chips and beat until combined.Collage: cookie dough, smashed and baked on cookie sheet.
  5. Scoop with a medium size cookie scoop and place 2 inches apart on parchment lined baking sheet.
  6. Smash with a fork. If the cookie dough is sticky, you can sprinkle with a bit of granulated sugar. 
  7. Bake the cookies for 8- 10 minutes. Collage: Monster cookies with reesse's pieces/ eyeball sprinkles added.
  8. Remove from oven and top with a few Reese’s Pieces.
  9. If you are decorating for Halloween, add the candy eyeball sprinkles. Wire rack with Monster cookies.
  10. Cool on a wire rack

Platter of monster cookies with eyeball sprinkles.

🟢 Recipe Notes

Storage: Store cookies in an airtight container at room temperature up to 7 days. 

Freeze the Dough: Scoop the dough and place onto a lined baking sheet. Freeze for 1 – 2 hours until cookie dough is firm. Place in freezer bags and freeze up to 3 months. Bake according to directions, adding 3-5 minutes baking time. 

Variations: Quick oats will work in place of old fashioned if that is what you have on hand. M&M’s candies can be substituted for Reese’s Pieces if you prefer them. 

Occasions: Monster cookies are perfect for birthday parties, Halloween and use red and green candies for a favorite for Christmas cookie exchanges.

Reese's Pieces Monster Cookies with candy eyeballs for Halloween stacked.

Monster Cookies stay soft and chewy and have a delicious peanut butter and chocolate flavor combo that everyone loves. A great everyday dessert that is easy to decorate for any holiday or celebration. 

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Monster Cookies with Reese's Pieces on a black tray.
Print Recipe
5 from 1 vote

Monster Cookies

Monster Cookies are chewy, flavorful and completely irresistible. One of our favorites to fill the cookie jar, these peanut butter oatmeal cookies are loaded with chocolate chips and Reese's Pieces. 
Prep Time10 minutes
Cook Time10 minutes
Total Time20 minutes
Course: Cookies
Cuisine: American
Keyword: chewy peanut butter oat cookies, Halloween cookies, monster cookies, peanut butter cookies with oats and chocolate chips, Reese's pieces cookies
Servings: 36 cookies
Calories: 164kcal
Author: Milisa

Ingredients

  • 1/2 cup softened butter
  • 1 cup brown sugar
  • 1 cup peanut butter - creamy or crunchy
  • 2 large eggs
  • 2 teaspoons vanilla extract
  • 1 1/4 cup all purpose flour
  • 1 cup old fashioned oats
  • 1 teaspoon baking soda
  • 1/2 teaspoon kosher salt
  • 1 cup semi-sweet chocolate chips
  • 1 cup Reese's Pieces candies
  • candy eyeball sprinkles optional

Instructions

  • Preheat oven to 375°F.
  • Add butter and brown sugar to bowl and beat with an electric mixer 2 minutes.
  • Next, add peanut butter, eggs and vanilla, mixing until combined.
  • Add flour, oats, baking soda and salt, mix thoroughly.
  • Mix in the chocolate chips until well combined.
  • Use a medium cookie scoop and place dough 2 inches apart on a greased or lined baking sheet.
  • Mash cookies with a fork crosswise. If the dough is sticky, sprinkle with a bit of granulated sugar.
  • Bake for 10-12 minutes or just until edges are lightly browned.
  • Press a few Reese's Pieces and candy eyeball sprinkles if desired into the baked cookies
  • Cool cookies on a wire rack.
  • Store cooled cookies in an airtight container up to 7 days.

Notes

Store cookies in an airtight container at room temperature up to 7 days. 
Freeze the Dough: Scoop the dough and place onto a lined baking sheet. Freeze for 1 - 2 hours until cookie dough is firm. Place in freezer bags and freeze up to 3 months. Bake according to directions, adding 3-5 minutes baking time. 
Variations: Quick oats will work in place of old fashioned if that is what you have on hand. M&M's candies can be substituted for Reese's Pieces if you prefer them. 
Occasions: Monster cookies are perfect for birthday parties, Halloween and use red and green candies for a favorite for Christmas cookie exchanges.

Nutrition

Serving: 1g | Calories: 164kcal | Carbohydrates: 18g | Protein: 4g | Fat: 9g | Saturated Fat: 4g | Polyunsaturated Fat: 4g | Cholesterol: 17mg | Sodium: 106mg | Fiber: 1g | Sugar: 11g
5 from 1 vote (1 rating without comment)

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