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    Home ยป Recipes ยป Desserts (Baked) ยป Monster Cookie Bars: a Fully Loaded Cookie Bar Recipe

    LAST UPDATED: October 29, 2021 โ€ข FIRST PUBLISHED: October 27, 2019 By Toni Dash 33 Comments

    Monster Cookie Bars: a Fully Loaded Cookie Bar Recipe

    Jump to Recipe

    This post may include affiliate links. As an Amazon Associate I earn from qualifying purchases.

    Monster Cookies bars

    Monster Cookies are fully loaded with peanut butter, mini M&M’s, oats and topped with a chocolate drizzle. An easy, irresistible cookie bar recipe.

    Monster Cookies bars
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    Monster Cookies bars

    If you are a cookie lover but can’t pick which one you want, Monster Cookies are always the right choice.

    Chock full of the best of every type of cookie, the moist chewy cookie bar always satisfies cookie cravings! For a cookie version try our Reese’s Cookies or Peanut Butter Chocolate Chip cookies.

    Jump to:
    • What are Monster Cookies?
    • Recipe Ingredients
    • Key Cookie Bar Recipe Ingredients
    • How to Make Gluten-Free Monster Cookies
    • How to Make Monster Cookies โ€“ Step-by-Step
    • How to Store Monster Cookie Bars
    • More Baked Dessert Recipes Youโ€™ll Love
    • Recipe

    What are Monster Cookies?

    Combine the recipes for chocolate chip cookies, peanut butter cookies and oatmeal cookies you end up with a Monster cookie recipe.

    It’s a ‘super cookie’ full of favorite ingredients!

    Recipe Ingredients

    What’s in the Monster Cookies? Take a look!

    • All Purpose Flour (regular or gluten-free)
    • Baking Soda
    • Kosher Salt
    • Old Fashioned Oats
    • Unsalted Butter
    • Peanut Butter
    • Brown Sugar
    • Granulated Sugar
    • Egg
    • Vanilla Extract
    • Mini M&Ms
    • Chocolate Chips

    Key Cookie Bar Recipe Ingredients

    Old Fashioned Oats

    Old Fashioned Oats hold their shape and add fantastic texture to the Monster Cookies. They lend a homey flavor too.

    We recommend these over Quick Oats which tend to blend into the cookie bar recipe.

    If gluten-free, be sure to use gluten-free certified oats. Several brands sell them under the name ‘Old Fashioned Rolled Oats’.

    Mini M&Ms

    Traditionally most Monster Cookie recipes use regular size M&M’s. Those can be substituted.

    We use mini M&M’s in this recipe which ensures more M&M’s in the Monster cookie bars. More is better, right?

    Peanut Butter

    Peanut Butter gives so much flavor in this recipe! Use Smooth or Chunky style peanut butter. Either works great. Pick your favorite texture.

    Chocolate Chips

    Usually the chocolate chips are included IN the Monster Cookies. This recipe is changed up to melt them to drizzle on top of the cookie bar recipe.

    And then more mini M&Ms are added on top of the melted chocolate!

    Monster Cookie Bars side view

    How to Make Gluten-Free Monster Cookies

    To make this easy cookie bar recipe gluten-free swap these ingredients:

    Gluten-Free Flour

    Use a measure-for-measure gluten-free flour blend. Our recommendation is Bob’s Red Mill gluten-free 1-to-1 baking flour. It will provide a similar texture to regular all purpose flour.

    Gluten-Free Rolled Oats

    Ensure the oats used are certified gluten-free. Do not use Instant Oats.

    How to Make Monster Cookies – Step-by-Step

    Make this cookie bar recipe just once and you’ll be hooked. It’s SO easy!

    STEP 1. Preparation

    Preheat oven to 350 degrees. Line a 9×9 inch square pan with parchment paper or foil (sprayed with cooking spray).

    STEP 2. Make the dough

    In a large mixing bowl, whisk together flour, baking soda, salt, and oats (photo 1).

    In a second large mixing bowl using a hand mixer or bowl of a stand mixer fitted with a paddle attachment, cream together butter, peanut butter, and sugars (photo 2).

    Add egg and vanilla extract and beat for an additional 2 minutes (photo 3).

    Gradually combine the dry ingredients and wet ingredients mixing just until combined. Stir in M&M’s (photo 4). Evenly press dough into the prepared pan.

    Monster Cookies recipe steps photos
    Monster Cookie Bars in pan pre baking

    STEP 3. Bake and Cool

    Bake bars for 18-20 minutes or until edges are golden. A toothpick inserted into the center and should come out clean.

    Cool completely on cooling rack.

    STEP 4. Chocolate drizzle

    Melt chocolate chips in the microwave and whisk until smooth. Drizzle melted chocolate over bars and top with extra mini M&M’s.

    Let chocolate drizzle harden for about 30 minutes at room temperature or refrigerate for 15 minutes before slicing.

    Cut bars into 9 large squares or 12 mini squares.

    Monster Cookie Bars recipe

    How to Store Monster Cookie Bars

    Store fully cooled cookie bars in an airtight container.

    Cookies should be layered with wax paper or parchment paper in between layers. This prevents them sticking together.

    • Room Temperature: Store at room temperature for up to 3 days. 
    • Refrigerator: They may also be kept in the refrigerator for up to a week.
    • Freezer: The Monster Cookies can also be kept in the freezer for up to 3 months. 
    Monster Cookie Bars stack

    More Baked Dessert Recipes You’ll Love

    • Turtle Brownies in Jelly Jars
    • Chocolate Peppermint Oreo Brownies
    • Rustic Plum Cake
    • Great Grandma Jean’s Apple Pie
    • Cranberry White Chocolate Pecan cookies
    • Raspberry Cheesecake Cookies

    Did you make it? Please RATE THE RECIPE below!

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    Recipe

    Monster Cookies bars

    Monster Cookie Bars

    The best of every cookie recipe rolled into one 'super cookie' bar. Monster Cookies are full of peanut butter, M&Ms, oats and drizzled with chocolate in an easy cookie bar recipe.
    5 from 24 votes
    Print Save Recipe Recipe Saved! Pin Rate
    Course: Dessert
    Cuisine: American
    Prep Time: 10 minutes minutes
    Cook Time: 20 minutes minutes
    Cooling Time (in refrigerator): 15 minutes minutes
    Total Time: 45 minutes minutes
    Servings: 12
    Calories: 406kcal
    Author: Toni Dash
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    Ingredients

    • ¾ cup all-purpose flour regular or gluten-free measure-for-measure blend
    • ½ teaspoon baking soda
    • ¼ teaspoon salt
    • 1 ½ cups old fashioned oats
    • ½ cup unsalted butter room temperature
    • 2/3 cup peanut butter crunchy or smooth
    • ½ cup brown sugar
    • 1/3 cup granulated sugar
    • 1 large egg
    • ½ teaspoon vanilla extract
    • 1 cup mini M&M’s plus more for garnish
    • ½ cup chocolate chips

    Instructions

    • Preheat oven to 350 degrees.
    • Line a 9×9 inch square pan with parchment paper or foil.
    • In a bowl, whisk together flour, baking soda, salt, and oats; set aside.
    • In a large bowl, cream together butter, peanut butter, and sugars until light and smooth, about 3 minutes.
    • Add egg and vanilla extract and beat for an additional 2 minutes.
    • With the standing mixer or beaters running on low, gradually add the flour mixture, mixing only until just combined. Stir in M&M’s.
    • Evenly press dough into the prepared pan. Bake bars for 18-20 minutes or until edges are golden and a toothpick is inserted into the center and comes out clean. Cool completely.
    • Place the chocolate chips in a small microwave safe bowl. Microwave on 50% power for 45 second intervals until the chocolate chips are melted; whisk until smooth.
    • Drizzle melted chocolate over bars and garnish with M&M’s. Let chocolate drizzle harden for about 30 minutes at room temperature or refrigerate for 15 minutes before slicing.
    • Cut bars into 9 large squares or 12 mini squares.

    Video

    Notes

    How to Store Monster Cookies
    Store fully cooled Monster Cookies in an airtight container.
    Cookies should be layered with wax paper or parchment paper in between layers. This prevents them sticking together.
    Room Temperature: Store cookies at room temperature for up to 3 days.
    Refrigerator: They may also be kept in the refrigerator for up to a week.
    Freezer: The Monster Cookie Bars can also be kept in the freezer for up to 3 months.

    Nutrition

    Calories: 406kcal | Carbohydrates: 47g | Protein: 7g | Fat: 22g | Saturated Fat: 10g | Cholesterol: 38mg | Sodium: 186mg | Potassium: 155mg | Fiber: 3g | Sugar: 31g | Vitamin A: 312IU | Vitamin C: 1mg | Calcium: 53mg | Iron: 1mg
    Monster Cookies bars
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    Did you make this recipe?Mention @boulderlocavore or tag #boulderlocavore!
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    Reader Interactions

    Comments

    1. Katie says

      October 31, 2019 at 7:34 am

      5 stars
      These bars are a combination of all of my favorite Halloween treats as a child! Peanut butter, chocolate, m&m’s- I love them!

      Reply
    2. Lyanna Soria says

      October 30, 2019 at 8:48 am

      5 stars
      This would be great to make for Halloween or during break time with my kids. I’m sure they would love this delicious looking treat full of yummy stuff.

      Reply
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    Welcome! Iโ€™m Toni Dash. Iโ€™m a Certified Nutrition Coach and the professional writer/blogger, photographer, recipe developer and creator of Boulder Locavoreยฎ. Iโ€™m so glad you are here!

    More about me โ†’

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