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.
If you are a cookie lover but can’t pick which one you want, Monster Cookies are always the right choice.
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!
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
- 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’.
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 gives so much flavor in this recipe! Use Smooth or Chunky style peanut butter. Either works great. Pick your favorite texture.
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!
How to Make Gluten-Free Monster Cookies
To make this easy cookie bar recipe gluten-free swap these ingredients:
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.
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.
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.
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
Monster Cookie Bars
- 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
- 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.