These monster cookie fudgy brownies are a double layer brownies. It has a super fudgy brownie layer loaded with chocolate chips. Then, monster cookie dough baked on top to create the ultimate brownie! If you want to up your next batch of brownies, you have to try these!

What Are Monster Cookies
Monster cookies are the type of cookie that has all the fix-ins. They are my favorite type of cookie!
These cookies are a cross between an oatmeal chocolate chip cookie and a peanut butter cookie. It is best of both worlds! This cookie has oats, peanut butter, mini m&m's and mini chocolate chips.
Steps To Make Cookie Dough
Since this monster cookie dough needs to be chilled before you use it, you need to make it first. Here is the steps to make it.
- Step 1: Dry ingredients- In a mixing bowl, mix the flour, cornstarch, baking soda, baking powder, and salt. The cornstarch helps make these a chewy cookie.
- Step 2: Wet ingredients- First, beat the butter and both sugars together. It needs to be light and fluffy before you add the peanut butter, vanilla, and egg.
- Step 3: Add dry ingredients into the wet- Add in the dry ingredients and mix until combined. Since there is peanut butter, it will be a wet dough.
- Step 4: Add the fillings- Now, add the oats, mini m&m's and mini chocolate chips. If you don't have mini versions, you can use the regular version.
- Step 5: Chill- This dough has to be chilled for 40 minutes before using to firm the dough.
How To Make The Brownie Batter
These brownies are based off my Better Than Boxed Brownies. I just reduced the quantity to prevent a huge brownie.
- Beat eggs and sugar- Beat these using a mixer with a whisk attachment. Beat for a whole 5 minutes to get the eggs light and fluffy. The air in the eggs is how to brownies will rise since there is no leavening agent.
- Add butter, oil, and vanilla- Add all three in, and mix on low to not knock out the air from the eggs.
- Mix in the dry ingredients- Pour it all in to bowl and use a rubber spatula to fold it in. This takes a few minutes, but keep going!
- Add in chocolate chips- The best part! My favorite brownies are the type with chocolate chips. There are two types to balance the chocolate flavor.
Prebaking The Brownie Layer
First, grab a 9X9 pan and spray with baking nonstick spray. Then, place parchment paper on the bottom and up the sides to easily remove the brownies later.
Now, these brownies normally need a long time to bake in the oven. Since the cookies don't need as long in the oven the brownies bake a little first, before adding in the cookie dough. We don't want to over cook the cookie layer, while the brownie layer is still too gooey!
After the brownies bake for 15 minutes, then grab the cookie dough by the handful and flatten it into a disc. Do this until all of the dough is used.
Decorating Tip
If you want more color and texture on top of the cookie layer, I sprinkle a lot of the mini m&m's and mini chocolate chips on top. I have tried to add extra topping after it baked, but the cookie was too set and the topping just fell off. If you want the topping, add it before you bake!
Cooling The Brownies
Now this is important, don't dig into these brownies until they are completely cool! I know it is hard to be patient, but the chocolate flavor taste very dull when still warm. Room temperature brownies, have a much stronger rich chocolate flavor.
Another reason is the brownies still cook as it cool. If you were to cut into the tray, it would be pretty gooey.
If you are dying for some brownies, pop the tray into the freezer for 25 minutes to cool it down faster. That is what I do, when I need the brownies now!
Cutting The Perfect Brownie
Once the monster cookie fudgy brownies are room temperature, take them out of the pan and place on a cutting board. Then, take a sharp knife and cut the brownies into 16 squares. After each cut, wipe the knife clean. This will give you the perfect brownie square!
Storing These Cookie Brownies
The monster cookie fudgy brownies should be stored at room temperature in an air tight container. They will last up to 5 days.
Other Brownie Recipes To Try
- White Chocolate Cinnamon Blondies
- Peanut Butter Cup Brownies
- Brown Butter Brookie Bars
- Small Batch Brownies
Make sure to tag me on Instagram @stephaniesweettreats and leave me a review below if you made these brownies. I hope you loved it! To get more ideas follow me on Pinterest.
📖 Recipe
Monster Cookie Fudgy Brownies
Ingredients
Brownies
- 1 â…“ cup White granulated sugar
- 2 Large eggs
- 1 Egg yolk
- 5 tablespoon Unsalted butter
- â…“ cup Oil canola or vegetable
- 1 teaspoon Pure vanilla extract
- ½ cup All-purpose flour
- ¾ cup Unsweetened cocoa powder dutch process
- 1 tablespoon Cornstarch
- ¼ teaspoon Salt
- ½ cup Semi-sweet chocolate chips
- ½ cup Milk chocolate chips
Monster Cookie Dough
- ½ cup All-purpose flour
- 1 teaspoon Cornstarch
- ½ teaspoon Baking soda
- â…› teaspoon Baking powder
- ¼ teaspoon Salt
- ¼ cup Unsalted butter room temperature
- â…“ cup Brown sugar packed light or dark
- â…› cup White granulated sugar
- ¼ cup Peanut butter creamy
- 1 teaspoon Pure vanilla extract
- 1 Large egg room temperature
- ½ cup Quick oats
- ½ cup Mini chocolate chips
- ½ cup Mini M&M's
Instructions
Monster Cookies
- In a medium sized mixing bowl, mix together flour, cornstarch, baking soda, baking powder, and salt.
- Using a mixer, beat the butter, brown sugar, and sugar together for 1 minute on medium. It should be light and fluffy. Add in the peanut butter and mix for another minute.
- Add in the vanilla and egg. Mix until combined. Scrape the bowl and mix again for 20 seconds.
- Slowly add the dry ingredients into the wet ingredients. Once combined, add in oats, m&m's, and chocolate chips. Cover and chill for 40 minutes.
Brownies
- When the cookies are almost done chilling, start the brownie batter. Preheat the oven to 325F. Spray a 9X9 pan with non-stick baking spray. Line the bottom and 2 sides of the pan with parchment paper. This will make it easier to take out of the pan.
- In a medium bowl, whisk the flour, cocoa powder, cornstarch, and salt. Set aside.
- Using a mixer, combine sugar, eggs, and egg yolk. Use a whisk attachment and beat for 5 minutes. Melt the butter while this beats so it can cool down slightly. Egg mixture will be very light and fluffy.
- Add in melted butter, oil, and vanilla. Mix on low until combined. Take off mixer. Add in all of the dry ingredients. Use a rubber spatula and fold in the dry ingredients. Be gentle to not knock any air out of the eggs. Add in the chocolate chips, and milk chocolate chips.
- Pour the batter in the pan. Use a rubber spatula to smooth the batter into the corners.
- Bake for 15 minutes for the brownie top to be set slightly before adding the cookie dough. Take dough out of the fridge. And take small handfuls of dough, and flatten into a disc shape. Top the brownies with the cookie dough discs. Continue until all of the dough is used
- Bake for another 20 minutes. Top with foil loosely to protect the cookie from over browning. Bake for another 5-10 minutes until the cookie and brownie is set. There should be no jiggle. Place brownies on cooling rack.
- Let the brownies cool completely. They should be completely room temperature before cutting into. Store at room temperature.
Christian says
They were so yummy!!!
Bethany Dell says
I made these for my husbands family, and they RAVED about them, the pan was sent back empty the same day. I’ve been asked to make them again just a week later. Huge hit!
Taylor says
These monster brownies are incredible! I made them for my friends & family & they were eaten SO quickly! Everyone loved them! They’re the perfect mix of everything & the brownie part was sooo fudgy! Seriously amazing, I can’t wait to make them again!
Taslima says
Hello
These look amazing!
I don’t have 9x9 inch pan. But if I were to use a 9x13 should I double the recipe?
Stephanie Rutherford says
Yes! Just double the recipe!
Kyle says
I love these brownies.
Tristan says
Absolutely delicious! One of my favorite recipes I've tried! And I couldn't just keep these all to myself, so I took some to work and shared with friends - they all raved about how delicious they were as well! I loved the combo of cookies, brownies, and just a little touch of peanut butter that made this the perfect combo for anyone with a sweet tooth!
So yummy! Can't wait to make these and more of Stephanie's recipes in the future!
Jessica says
The Brownie directions say baking soda but it’s not under the ingredients list…. How much baking soda in the brownie mixture?
Stephanie Rutherford says
Thank you for letting me know! There is no rising agent in the brownie mixture, so I think I added it to the instructions by accident. I fixed it. There is no rising agent in the brownies, because with a fudgy texture and the baking soda it cause it to rise while baking. Then, as it cools it would deflate dramatically. Taking out the rising agent out of the brownies fixed that problem!
TheKreMarke says
Amazing recipe!!! Worth the effort! Easy to follow and came out perfectly!! Our family loves it!
Shaz says
Have peanut and tree nut allergies,what’s would you suggest as a good substitute for the peanut butter-do you think cookie butter would work
Thanks
Stephanie Rutherford says
Yes cookie butter will work! Or sunbutter.
Khushboo Patel says
These Cookie Monster fudgy brownies were so good! They are super thick and delicious. The peanut butter, oatmeal, mini m&m’s and all the chocolate really compliment one another. Will be making them again!