These monster cookie bars are loaded with chocolate chips and M&M's, and have a delicious peanut butter flavor with a chewy texture!
These bars are the bar version of these delicious chewy monster cookies recipe. All you have to do is mix everything in one bowl (check the instructions of course), and bake it in a 9 by 9 inch pan!
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Why this recipe works
- These are made with plenty of M&M's, chocolate chips, and peanut butter!
- They are full of flavor from all the add-ins and peanut butter.
- These have the best crunchy on the outside and chewy and soft in the middle texture!
- This recipe can be made gluten-free or dairy free if needed! Check the substitution section for more information.
- This whole recipe comes together in one bowl! And is made with simple ingredients.
Ingredients
Before you start to make this recipe, measure and prepare your ingredients so the cooking process will go smoothly and easily.
Full measurements are in the recipe card below.
Butter- use unsalted butter for this recipe. Only butter will work for this recipe, no margarine, and no coconut oil. Margarine has a weird taste and can ruin the flavor of these delicious cookies.
Peanut butter- and peanut butter will work for this recipe, natural, processed, chunky, or smooth. The results will be different for each peanut butter kind. We prefer to use smooth store-bought peanut butter.
Rolled oats- we used rolled oats for this recipe, you can use old-fashioned oats or quick oats. Make sure that you are using gluten-free oats if you are gluten-free.
Flour– we used all-purpose flour for this recipe. cake flour will work great as well.
Baking soda – baking soda helps the cookies rise and spread. Make sure that your baking soda isn't expired. Don't replace baking soda with baking powder!
Sugar- we used granulated sugar for this recipe. You can use caster sugar as well.
Brown sugar- adds a caramelly flavor and chewy texture to the cookies.
Eggs- you will need 2 large eggs for this recipe. Make sure that your egg is at room temperature.
Egg yolk- egg yolk gives this cookie a chewier texture.
Vanilla extract- adds extra flavor.
Kosher salt- you will need about ½ teaspoon of kosher salt for this recipe.
M&M's- we used regular m&m's in this recipe, but feel free to use your favorite kind of m&m's, like mini m&m's, peanut butter m&m's, etc.
Chocolate chips- you can use any kind of chocolate chips for these cookies, we like to use either dark chocolate chips or semisweet chocolate chips.
Instructions
Preheat an oven to 180c (350f) and prep a parchment paper-lined 9 by 9 baking pan.
Into a big mixing bowl, add the room temperature butter and peanut butter, and cream it with an electric hand mixer for 2-3 minutes or until it's creamy and light in color.
Add the brown sugar, granulated sugar, vanilla extract, and kosher salt. Mix until well combined.
Add the egg and egg yolk and mix until the mixture is creamy and smooth.
Add the rolled oats, flour, and baking soda and mix until almost combined.
Add the chocolate chips and m&m's and mix until just combined.
Transfer the cookie dough to a parchment paper lined 9 by 9 pan and top with more chocolate chips and M&M's. Bake in a 180c (350f) preheated oven for 25-30 minutes until the edges are golden brown.
Do not overbake it to keep it chewy in the middle!
Expert Tips
- Use room temperature ingredients. It is important that you use room-temperature ingredients like eggs and butter. This step ensures that your mixture mixes into a homogenous mixture and bakes perfectly.
- Don’t overmix the batter, you don’t want to develop the gluten in the flour. This step ensures you have moist cookies and not dense and dry cookies.
- Make sure that your butter is at room temperature. An hour or two before making these cookies, take the butter out of the fridge and let it come to room temperature. The butter should be soft to the touch. If your butter is too cold, it will be harder to mix and there will be lumps of butter in the dough.
- Measure your flour correctly! When measuring your flour, avoid scooping it with a measuring cup. Instead, stir the flour with a spoon to create as many air pockets as possible, and spoon it into your measuring cup. Finally, level it with a back of a knife.
- Line your baking pan with parchment paper! This step helps the cookie bars to bake evenly, and it makes sure that your bars release easily from the pan.
- Be patient! I know it’s extremely tempting to eat these bars as they are pulled out of the oven, but let them cool for at least 30 minutes so they will be more firm and won’t crumble up.
Faq's
These cookies have a peanut butter flavor, mixed with melted chocolate and M&M's.
Monster cookie bars are made of cookie dough filled with chocolate chips, M&M's, peanut butter, and oats. They have an extra soft and thick texture that is hard to resist!
Yes. Quick oats are perfect if you are looking for a less chewy texture. Both are delicious!
These will last for up to 4 days at room temperature.
Storing
Store these in an airtight container at room temperature for up to 4 days. I love microwaving the bars for 10 seconds to get them moist and fresher!
Freezing
To freeze these, you will need to wrap the bars in plastic wrap or foil and seal them in an airtight container or in an airtight resealable bag. You can freeze them for up to 2 months.
Substitutions
Dairy-free- to make these cookie dairy free, swap the butter with vegan dairy-free butter, and ensure that you are using dairy-free chocolate chips. Also, use dairy-free m&m's.
Gluten-free- to make these dairy free, swap the all-purpose flour with gluten-free flour.
Variations
M&M's- you can make these Christmas themed by swapping the M&M's with Christmas M&M's or make these valentines day themed by using valentines day M&M's.
Mix-ins- you can add your favorite mix-ins like white chocolate chips, toffee, pretzels, chocolate chunks (milk or dark chocolate), mini chocolate chips, etc.
More bars recipes
Pumpkin bars- These gluten free pumpkin bars are soft and have a moist crumb, and are topped with a silky smooth cream cheese frosting.
Lemon bars with graham cracker crust- These lemon bars with graham cracker crust are super easy to make. They are made with a zesty and creamy lemon filling and are topped with plenty of powdered sugar.
White chocolate brownies- These white chocolate brownies are made with white chocolate and are fudgy, and filled with white chocolate flavor.
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📖 Recipe
Chewy Monster Cookie Bars
Ingredients
- 80 g Butter softened
- ½ cup Peanut butter creamy, skippy or jeff style
- ½ teaspoon Kosher salt
- 2 teaspoon Vanilla extract
- ½ cup Brown sugar
- â…“ cup Granulated sugar
- 1 Eggs
- 1 Egg yolk
- 1 cup Rolled oats
- 1 cups Flour
- ½ teaspoon Baking soda
- ¾ cup Chocolate chips plus more for the top
- ½ cup M&M plus more for the top
Instructions
- Preheat an oven to 180c (350f) and prep a parchment paper-lined 9 by 9 baking pan.
- Into a big mixing bowl, add the room temperature butter and peanut butter, and cream it with an electric hand mixer for 2-3 minutes or until it's creamy and light in color.
- Add the brown sugar, granulated sugar, vanilla extract, and kosher salt. Mix until well combined.
- Add the egg and egg yolk and mix until the mixture is creamy and smooth.
- Add the rolled oats, flour, and baking soda and mix until almost combined.
- Add the chocolate chips and m&m's and mix until just combined.
- Transfer the cookie dough to a parchment paper lined 9 by 9 pan and top with more chocolate chips and M&M's. Bake in a 180c (350f) preheated oven for 25-30 minutes until the edges are golden brown.
- Do not overbake it to keep it chewy in the middle!
Notes
- Use room temperature ingredients. It is important that you use room-temperature ingredients like eggs and butter. This step ensures that your mixture mixes into a homogenous mixture and bakes perfectly.
- Don’t overmix the batter, you don’t want to develop the gluten in the flour. This step ensures you have moist cookies and not dense and dry cookies.
- Make sure that your butter is at room temperature. An hour or two before making these cookies, take the butter out of the fridge and let it come to room temperature. The butter should be soft to the touch. If your butter is too cold, it will be harder to mix and there will be lumps of butter in the dough.
- Measure your flour correctly! When measuring your flour, avoid scooping it with a measuring cup. Instead, stir the flour with a spoon to create as many air pockets as possible, and spoon it into your measuring cup. Finally, level it with a back of a knife.
- Line your baking pan with parchment paper! This step helps the cookie bars to bake evenly, and it makes sure that your bars release easily from the pan.
- Be patient! I know it’s extremely tempting to eat these bars as they are pulled out of the oven, but let them cool for at least 30 minutes so they will be more firm and won’t crumble up.
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