Brownie Monster Cookie Bars
These brownie monster cookie bars are an easy twist on classic bar cookies, with a brownie base and a peanut butter cookie top to make peanut butter brookie bars. They come together in three simple steps – prep the brownie mix, make the cookie dough, mix in your oatmeal, chocolate chips, and candies, and then layer them together in the pan before baking. This brownie monster cookie bar recipe is not only incredibly easy to whip up but also allows for creative substitutions, variations, and helpful tips.
Bar cookies are my preferred cookie state. I have no patience for baking either. So these cookie bars were inspired by this caramel brookies recipe but also mixed with the monster cookie bars. The mixture of chocolate chip cookies and brownies is simply the best. Mix in the peanut butter and you will have this family swooning.
Ingredients for Monster Brookie Bars
The mixes for both the peanut butter cookies and brownies make these bar cookies a cinch to make.
- Brownie Mix – 1 box of your favorite brownie mix
- Peanut Butter Cookie Mix – 1 box of peanut butter cookie mix or you can make this easy gluten free peanut butter cookie dough.
- Eggs and vegetable oil (as per the package instructions)
- Water (as per the package instructions)
- oatmeal – I used old-fashioned rolled oats but quick oats can also be used.
- peanut butter – Whichever peanut butter you have in the cupboard is fine – smooth or chunky peanut butter works just fine. My preference is Jif creamy peanut butter.
- chocolate chips – Semi-sweet chocolate chips, dark chocolate chips, or milk chocolate chips are all going to work in this recipe.
- Candy – candy-coated chocolate candy like mini M&M’s work great as a stir in.
- peanut butter chips – I am overly obsessed with Reese’s peanut butter chips.
See the recipe card for quantities.
Instructions for How to Make Brownie Monster Cookie Bars
To make these monster brookies, start by preheating the oven to 350 degrees.
Prepare the brownie mix as directed on the package in a large bowl, then spread into a greased 9×13 baking dish. Bake the brownies for 10 minutes.
In a separate bowl, prepare the peanut butter cookie mix as directed on the package. Mix in the oatmeal, peanut butter, chocolate and peanut butter chips, and candies to make the monster cookie dough.
Either spread out the cookie dough on a cutting board mat and then place it on the partially baked brownie layer or drop in smaller flat pieces on the brownies to make the monster cookie layer.
Bake the fudgy brownie monster cookie bars for another 15-20 minutes. Let cool for 10-20 minutes before cutting.
Cut the fudgy brownie monster cookie bars into large or small squares. These make perfect bite-sized brookie bars or nice big brownies that are served warm and are perfect with ice cream, hot fudge, and whipped cream. Either way, they are the ultimate dessert to serve your family.
Hint: To ensure easy removal and a clean presentation, thoroughly grease the baking pan or line it with parchment paper.
Substitutions
If you want to make these but want to make sure everyone with special diets can enjoy them, here are some ideas on how to make them with substitutions.
- Gluten-Free Option:
- Choose gluten-free versions of the brownie and peanut butter cookie mixes for a delectable treat suitable for those with gluten sensitivities.
- Vegan Twist:
- Opt for vegan brownie and peanut butter cookie mixes. Substitute eggs with flax or chia eggs, and use plant-based oil to make a scrumptious plant-powered version.
- Nut-Free Variation:
- If allergies are a concern, select nut-free brownie mix and consider using sunflower seed butter in place of peanut butter for a safe and equally delicious alternative.
Variations
Change up these double-layered brownie and monster cookie bars with these ideas for variations.
- Double Chocolate Delight:
- Add a cup of chocolate chips to the brownie batter for an extra dose of chocolatey goodness.
- Nutty Paradise:
- Fold in chopped nuts like walnuts or pecans into the peanut butter cookie dough for a delightful crunch.
- Caramel Swirl Sensation:
- Drizzle caramel sauce over the top of the bars before baking for a decadent, gooey twist.
Add a caramel layer between the brownies and monster cookie dough with this caramel brookie bar recipe.
Equipment
Get everything you need delivered to you from Amazon to make these brookie bars – monster cookie style. Check out the Amazon store for all the go-to ingredients and equipment.
Storage
Store the baked monster cookie bars in the fridge or freezer. Then just bring to room temperature by setting out on the counter.
Top tip
- Properly Grease the Pan:
- To ensure easy removal and a clean presentation, thoroughly grease the baking pan or line it with parchment paper.
- Testing Doneness:
- Use a toothpick to check the doneness of the bars. Insert it into the center, and if it comes out with a few moist crumbs (but not wet batter), the bars are ready.
FAQ
Monster cookies are peanut butter cookies with oatmeal, chocolate chips, and M&M’s in them.
Cookie Dough!! This backed brookie bar recipe is always going to be a favorite recipe.
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These are my favorite snacks that always go well with a sweet snack.
Brownie Monster Cookie Bars
Equipment
Ingredients
- 18.3 ounce box of fudge brownie mix plus package ingredients
- 17.5 ounce peanut butter cookie mix plus package ingredients
- ½ cup oatmeal
- ½ cup peanut butter
- ½ cup semi-sweet chocolate chips
- ½ cup peanut butter chips
- ⅓ cup mini m&m's
Instructions
- Mix the brownie mix together based on package directions and bake for 10 minutes.
- While the brownies are baking, mix together the peanut butter cookie mix together according to the package directions.
- Stir the chocolate and peanut butter chips, m&m's, oatmeal, and peanut butter into the cookie dough.
- Then drop crumbled pieces of the chocolate chip cookie dough over brownie mix or press out on a baking matt and lay over the brownies.
- Bake on 350 for 20 minutes or until the cookie top is golden brown.
- Let cool for 15 minutes before cutting.
Notes
-
Properly Grease the Pan:
- To ensure easy removal and a clean presentation, thoroughly grease the baking pan or line it with parchment paper.
-
Testing Doneness:
- Use a toothpick to check the doneness of the bars. Insert it into the center, and if it comes out with a few moist crumbs (but not wet batter), the bars are ready.
Nutrition
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