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Tuesday made better with Monster Oatmeal Chocolate Chip Cookie Bars for snacking. These one bowl homemade oatmeal cookie bars with chocolate chips andย Reeseโs Pieces are the perfect way to use up any leftover Halloween candy. Theyโre super easy, festive for both Halloween and Thanksgiving, and most importantly, everyone LOVES them!
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Itโs been so long since I shared a simple cookie bar. But with Halloween right around the corner, I figured now was the perfect time.
We donโt get trick-or-treaters up here where we are, itโs a little too rural. Asher goes into Frisco where she goes to school and where the businesses on Main Street hand out candy. But she never brings much, if any, home.ย In general, we really donโt eat candy, and I donโt usually love using candy in my baking recipes. But sometimes, mostly for fun holidays like Halloween and Christmas, I cave in and throw some candy into desserts.
The Halloween candies that we always have a lot of around hereโฆM&Mโs and Reeseโs Pieces. I tend to buy way more than weโll actually ever eat. I get so excited when they come out with the fall colorsโฆfollowed by the holiday colors (Iโm such a sucker for any kind of holiday packaging), that I buy one too many bags and never know what to do with them all.
Enter these oatmeal chocolate chip bars. I mean, itโs Halloween, so I figure, if thereโs ever a time to have fun with a candy filled recipe, itโs now. You know?
A simple oatmeal cookie dough base studded with chocolate chips and your favorite leftover Halloween candy. I used Reeseโs Pieces, but M&Mโs or your favorite chopped up candy bar would be great too. Use what you, your family, and friends love most.
As you can guess, these are pretty easy to make.
I used my momโs oatmeal chocolate chip cookies recipe as a base (which is from the HBH cookbook). Then I stir in some candy pieces (again, use your favorite, chopped Reeseโs would be so good too). I also decided to bake the cookies into chewy bars, instead of round cookies. Momโs recipe is honestly the BEST. Nothing beats it, and the fact that itโs a one bowl and done kind of recipe makes them that much better.
Bonus? I pretty much always have the ingredients on hand. So itโs the perfect recipe to bake up whenever a craving for oatmeal cookies hits. And yes, along with this bar being easy to make, theyโre also so delicious. Best oatmeal cookies. Ever.
And I really mean it.
I baked these up with my little sister, Asher in mind. Sheโs been begging me to make cookies. She has a class Halloween party coming up that I promised to bake something for, so we tested these oatmeal bars out over the weekend. These are full on Asher approved. The thing with kids? They tend to be picky, so I knew I could be getting into trouble with the oatmeal cookie. But I really wanted to bake up something other than just another chocolate chip cookie. Been there done that. I was worried, but when she came down to the studio on Saturday, she ended up loving every bite. She could not get enough.
Granted, she loved the โHalloweenโ colored candies. But she also said the cookies were delicious. Sheโs so excited to make them again for her Halloween party.
Side Note: Asher is now ten. When I asked her what she was going to be this year, she said, โyouโll have to wait until Halloween to find outโ. And with sass. Ugh. I wish sheโd just stop growing up already!
Whenever I make the recipes I grew up baking with my mom, those more classic recipes, I always ask myself, why donโt I bake these more. Obviously itโs because I am constantly testing out new recipes. But itโs a bummer that itโs hard to find time to bake anything thatโs โoldโ and from the archives. Iโm glad I decided to dust this recipe off and share it with you guys.
Sometimes I forget that itโs the classic recipes that are really the greatest. Hands down a favorite recipe of the month. And I love that these are fun for both Halloween and Thanksgiving.
If you make these cookie bars please be sure to leave a comment and/or give this recipe a rating! Above all, I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, donโt forget to also tag me onย Instagram!ย Looking through the photos of recipes you all have made is my favorite!
Monster Oatmeal Chocolate Chip Cookie Bars
Ingredientsย
- 2 1/2 cups old fashioned oats
- 2 cups all-purpose flour
- 1 cup brown sugar packed
- 1/2 cup granulated sugar
- 1 teaspoon baking soda
- 1 teaspoon salt
- 1 cup canola oil
- 2 large eggs
- 1 tablespoon vanilla extract
- 1 1/2 cups semi-sweet chocolate chips
- 1/2 cup Reeseโs pieces or M&Mโs
Instructionsย
- 1. Preheat the oven to 350 degrees F. Grease a 9ร13 inch baking dish with butter or line with parchment paper.ย 2. In a large mixing bowl or the bowl of a stand mixer, mix the oatmeal, flour, brown sugar, granulated sugar, baking soda, salt, canola oil, eggs and vanilla. Beat until the dough is moist and all the ingredients are combined. The dough will be crumbly. Mix in the chocolate chips and 1/4 cup candy pieces.3. Press the dough into the prepared baking dish and scatter the remaining 1/4 cup candy over top. Transfer to the oven and bake 18-20ย minutes or until the edges are set and the bars are golden. Let cool and then cut into bars.ย
Nutrition
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Did you make this recipe? Please rate & comment below.
We love this recipe but sometimes it doesnโt bind together enough to be able to cut it into true squares. Wheat should I do to fix this? Should I add another egg? Thanks!
Hey Renee,
Thanks so much for making these cookie bars:) You could try adding another egg, also be sure to press the dough firmly into the baking dish. I hope this helps!
Delicious but absolutely fall apart! I did wait until they were cool before I cut them. Bummer because I didnโt test them and this is what Iโm bringing to a party now.
Hi Heidi,
Thanks for trying this recipe and sharing your feedback. So sorry to hear they fell apart. I hope they are enjoyed!
Could you add cinnamon?
Hi Jill,
Totally, that will work well for you! I hope you love this recipe, let me know how it turns out!
Iโm a fellow Frisco Coloradoan – Iโm curious if I need to modify this recipe for our high elevation (9100โ)?
Hey Jennifer,
You should be able to follow the recipe as written without any issues:) Please let me know if you give these cookies a try, I hope you love it! xT
How many days do these taste fresh for? Iโm trying to forecast a long to do list prior to a weekend of food prep for fall camping and if I can make these in advance it would help me!
These should stay fresh for about 4-5 days! You can always freeze the baked cookies and the dough as well! xT
Great recipe! We love monster cookies and this recipe is great because you donโt have to cream the butter and sugar. It mixed up great and tastes Yummy! This is a great base recipe for all kinds of mix ins; nuts, toffee chips, pretzels or mini marshmellows! Thank you
Thanks so much Lori:) I appreciate you making these cookies and your feedback! Happy Sunday! xT
Always make one of your recipes and the results are incredible! Here in Brazil, we don’t usually prepare bars, but I always see them here and they seem suitable for benefits in which many recipes are made, as they are practical, just cut and serve! I chose this recipe for my birthday, because some friends would bring their little children and the bars are colorful! It was a great success! We love it! Thanks for sharing amazing recipes!
Thank you so much Marisa! So cool these recipes have reached you in Brazil! ๐ xT
I made these for a party and they came out great! Everybody enjoyed them. I was a bit nervous to make them based on some of the prior comments, but I didn’t have any problem with them crumbling. I baked them for 25 minutes. I wonder if the people with the crumbling problem overbaked them? My only problem was that the candies on top fell off when I was cutting them, and I had even pushed them down into the bars before baking. I had a coupon for M&M’s so I used peanut butter M&M’s instead of Reese’s Pieces, and they were a little larger, so maybe that was the problem. Anyway, they were great!
Hey Amy,
I appreciate you making this recipe and sharing your feedback, so glad to hear that they turned out well for you! xT
Planning on making these tonight; do you think butter could be subbed for the oil?
Hey Gabrielle,
Yes, you could use an equal amount of melted butter. Please let me know if you have any other questions, I hope you love this recipe! xx
I havenโt made these yet, but I am excited to. Is there really 1,700 per bar?! Or is this per batch? Thanks!
Hey Katy,
It might be per batch! I always recommend that if the nutritional information is important to you, you use your own personal calculator. Ours is automatic and controlled by google. Itโs not something weโd prefer to be using. We are required to. Iโm sorry for the trouble, we do our best! Hope you enjoy the recipe! xT
Excellent bar cookie. I baked in parchment paper pan with overhang and lifted completely cooled bars out of pan for cutting. I had no problem with bars holding their shape but did cut bars in about 1″ x 2″ each. So much easier to cut when out of pan. Loved that recipe uses canola oil verse butter. Thanks for a great recipe!
Hey there,
Fantastic!! I love that this recipe turned out tasty for you, thanks so much for giving it a try! xx
Easy to make, and taste great, but I would NOT recommend making these for a gathering/classroom/work function. They do not hold their bar shape at all, and really need to be eaten with a spoon. They are quite messy if you attempt to hold them – they disintegrate in your hand. The only binding ingredients here are oil and egg, and oil does not provide structural integrity.
Iโve made them twice and enjoyed them but will probably try something else next time, as when I make bars it usually is for a group event.
Hi Robyn,
Thanks so much for making this recipe and sharing your feedback! So sorry these have been falling apart for you, they are a delicate bar:) xx
When I make these, I add an extra egg, and I sub 1/2 cup softened butter for 1/2 cup of the oil. It gives the bars a little more structure.
I don’t find it makes much difference whether you cream the butter and sugar or just beat it all well with a wooden spoon before adding the eggs and then remaining ingredients.
Delicious, easy and makes a ton. Reese Pieces are a must. This is a keeper.
Hey Kristy,
Awesome!! I am thrilled to hear that this recipe was a winner, thanks so much for trying it out! Have a great weekend! ๐ป
These are amazing, so much simpler than drop cookies but same texture, love love, will be in heavy rotation !!!
Hey Nicki,
Awesome!!๐คฉ I truly appreciate you making this recipe and sharing your review and love to hear that it was a hit! xTieghan
Hi Tieghan, just made these & they came out great! Just wondering – do you think the vegetable oil can be substituted for coconut oil?
Hey Krysten,
Perfect! I appreciate you making this recipe and sharing your feedback, I am so glad it was a hit! Yes, coconut oil would be great! xx