This post may contain affiliate links. Please see disclosure form more information.
These soft and chewy monster cookie bars are a delicious mix of creamy peanut butter, oats, chocolate chips and M&M’s in an easy-to-make bar cookie form. The perfect sweet treat for any occasion!
This delicious monster cookie bars recipe makes the cookie bar version of my family’s favorite monster cookies. They’re NOT for Halloween, although you can dress them up for any holiday. The word monster just refers to the mish mash of ingredients that go into this easy cookie recipe.
The best part about this easy recipe for monster cookie bars is you get all of the flavor of your favorite cookies without the work. No rolling, scooping or chilling dough — just press, and bake! For an even easier version, try my monster cookie dip!
Monster Cookie Bar Recipe Ingredients
Here’s a quick list of what you need to make the bars. Full amounts are in the printable recipe card below.
- All purpose flour — some versions are flourless, but flour gives a classic bar cookie texture.
- Oats — Either quick or old fashioned oats work here. Quick oats are not as chewy.
- Peanut butter — either creamy or crunchy will work
- Brown sugar and white sugar — for sweetness and texture
- Butter — either salted or unsalted butter
- Eggs — to bind the ingredients
- Baking soda — helps the bars rise
- Vanilla extract — for flavor
- Chocolate morsels — We like semi sweet, but use your favorite here.
- Sea salt and cinnamon — for flavor
- Mini M&M’s — You can use regular ones or even peanut M&M’s. You can also swap in your favorite chopped candies. These bars are very easy to customize! We like to top with flake salt for even more flavor.
How to Make Monster Cookie Bars
First, you cream the peanut butter and butter using an electric mixer. Then, gradually mix in your wet ingredients. Finally, mix in your dry ingredients using a rubber spatula. The dough will be very thick! Press the cookie dough into a baking dish, top with the chocolate candies and extra chips, and bake for about 30 minutes or until a light golden brown.
Allow the bars to cool down a bit. Then, carefully lift them out of the pan to finish cooling. If you can’t wait, you can slice them when warm. They are very gooey and the chocolate will melt all over your hands, but oh well!
Recipe Tips
Spray the baking pan with non stick spray and use parchment paper to easily lift the bars out for even slicing. The spray helps to keep the parchment paper in place.
Don’t over bake. The center may seem soft, but will firm up as the bars cool down.
Storage Tips
When completely cool, place the bars into an airtight container, and store at room temperature for 4-5 days. A slice of sandwich bread added to the container will help them stay soft longer. You can place the bars into the freezer and freeze for up to 3 months for best taste.
More Easy Dessert Bars
Try my sugar cookie bars or chocolate chip bars or double chocolate chip bars, oatmeal chip bars or my easy cake mix bars next!
Monster Cookie Bars
Ingredients
- 1 cup butter softened
- ½ cup creamy peanut butter
- 1 cup firmly packed brown sugar
- 1 cup granulated sugar
- 2 large eggs
- 2 teaspoons vanilla extract
- 2 cups all purpose flour
- 1 teaspoon baking soda
- 1 teaspoon sea salt
- 1 teaspoon ground cinnamon
- 1¼ cups rolled oats
- 1¼ cups semi sweet chocolate chips plus extra for the top
- 1 cup mini m&ms plus extra for the top
Instructions
- Preheat oven to 350℉ and prepare a 9×13 baking dish with parchment paper or nonstick spray
- In a large mixing bowl, beat the butter and creamy peanut butter together until creamy and all lumps are gone
- Add in the brown sugar and granulated sugar and cream until fluffy and well combined
- Beat in the eggs and vanilla extract
- Add flour, baking soda, sea salt and ground cinnamon and mix well
- Stir in the oats, chocolate chips and mini m&ms until fully combined
- Evenly spread the dough into prepared baking dish
- Top cookie bar dough with extra chocolate chips and mini m&ms
- Bake for 30 minutes, or until edges are lightly brown and a toothpick comes out clean
- Remove from oven, allow to cool slightly, then transfer to wire rack or cool surface to cool completely
Video
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Follow me on social media and sign up for the newsletter for the latest easy recipes.
