OREO O’s Treats

These crunchy marshmallow OREO O’s Treats speckled with pieces of OREO Cookies make a fun kid-friendly afternoon snack and they are so easy to make using just four ingredients.

In about 15 minutes, you can make an entire batch of these gooey chocolate cereal squares for your whole family to enjoy.

Grab a glass of cold milk to enjoy with these chocolatey OREO Cereal Bars. 

If you have not tried OREO O’s Cereal, you should grab a box next time you are at the store. 

The ring-shaped, chocolate, multi-grain cereal has a rich cream coating and the crunchy O’s have that familiar OREO Cookie flavor that we know and love. 

To make these treats all you need to do is blend the OREO O’s cereal with melted butter, marshmallows, and OREO Cookie pieces, but you’ll need just the right ratio to make the treats delicately chewy. 

When making a cereal treat using kid’s cereal, we always start with our BEST rice krispie treat recipe. and adjust the amount of cereal based on the shape and size of the pieces. Our original recipe calls for a ratio of 4 2/3 cups of cereal to 10 ounces of marshmallows and 4 tablespoons of butter.

For this recipe, we’ll keep the butter and marshmallows the same and add 6 cups of cereal and 20 broken OREO Cookies. 

The treats are still nice and chewy but they aren’t overly sticky. 

We always suggest you use European-style salted butter and fresh marshmallows to give your treats the best flavor.

Have questions about making cereal treats? Check out our FAQ page. (Or leave a comment and we’ll be happy to help!)

You can see more recipe ideas for using a variety of cereal to make Cereal Treat Recipes, here. 

how to make marshmallow OREO O’s Cereal Bars

you will need:

OREO O’s CEREAL

• You’ll use 6 cups of the OREO O’s cereal (30 grams or 1.41 ounces) in this cereal treat recipe. 
• Each cocoa-flavored corn and oat “O” has a rich cream coating so it tastes like an OREO Cookie.

OREO COOKIES

• Break up 20 cookies into small pieces and toss them with the cereal to give these treats a decadent OREO Cookie flavor. 
• If you’d like to ensure you have some nice cookie pieces on top of your OREO Cookie bars, reserve some of the cookie pieces to press on top of the pan of marshmallow treats. 

MARSHMALLOWS

• You’ll need 10 ounces of marshmallows.
• Always use the freshest marshmallows you have on hand. Fresh marshmallows make more delicately chewy treats. 
• If you can’t find a 10-ounce bag of marshmallows you can usually use 40 regular-size OR 6 cups of mini marshmallows. Different brands of marshmallows do weigh different amounts, so it’s always best to use the measurement listed in the nutrition label. 

BUTTER

• We have found that European-style salted butter provides the best flavor in our cereal treats recipes. You’ll be amazed at the difference good butter will make in this recipe.
• In our taste test, we found that 4 tablespoons (1/4 cup, 1/2 stick, 56.7 grams) of butter will give the treats the richest flavor. 
• We recommend using KeriGold or President Butter but Kroger Private Selection French-style Butter is great too. 

TOOLS YOU’LL NEED: 

• 9-inch square baking pan 
• large mixing bowl
• silicone spatula or large mixing spoon
• butter or cooking spray to grease your pan, bowl, and spatula (I prefer the flavor of butter, but the non-stick spray works too.)

buy ingredients & supplies

You can find the ingredients and supplies to make these Oreo O’s marshmallow cereal treats from Amazon. I earn a small commission for any sales when you use the links below at NO extra cost to you. 

Let’s make some OREO Cookie Cereal Bars…

step one: prep your equipment 

• Grease a large mixing bowl, your square 9-inch pan, and a silicone spatula with softened butter or spray with baking spray.
• Pour 6 cups of Oreo O’s Cereal into the bowl.  
• Break 20 OREO Cookies into small pieces.
• Sprinkle the cookies over the cereal, reserving some pieces to sprinkle over top of the treats, if desired. 

step two: melt the butter and marshmallows 

stovetop method:

1. Cut 4 tablespoons of European-style salted butter into 4 pieces. 
2. Place in a medium saucepan and set over low heat. 
   • Using low heat is important. It will allow your marshmallows to melt slowly and not overheat. 
   • If you overheat your marshmallows, the sugars in the marshmallows will begin to caramelize so when you blend them with the cereal they will produce hard treats instead of chewy treats. 
3. Allow the butter to begin melting, then stir in 10 ounces of marshmallows. 
   • I prefer using mini marshmallows as they melt quickly but you can use traditional large marshmallows as well. 
   • Just be sure to stir them often, so they don’t overheat. 
4. Continue to heat over low heat, stirring often, until about 75% of the marshmallows have melted.
5. Then remove the pan from the heat and stir the marshmallows vigorously, smashing them as needed, until melted. 
   • By taking the pan off the stove at this point, you will ensure your marshmallows don’t overheat and stay nice and soft.
   • It may take a minute of stirring before all the marshmallows melt. Just keep stirring and smashing. You’ll thank me when you have delicately chewy treats that are easy to eat. 

alternate microwave method:

1. In a large, microwave-safe bowl, place 4 tablespoons of salted butter and 10 ounces of marshmallows.
2. Microwave on high for 1 minute then remove and stir vigorously, using the residual heat to fully melt the marshmallows.
   • Once again, you don’t want to overheat the marshmallows as this causes your cereal treats to be too hard. 
   • You need to use a large mixing bowl when melting the marshmallows in the microwave as the marshmallows will puff up a lot. 
3. If needed, you may microwave for additional 15-second intervals, stirring vigorously until melted. 

step three: mix everything together 

1. Pour the melted marshmallow mixture over the OREO O’s Cereal in the bowl.
2. Stir gently until all of the cereal is coated evenly.

step four: spread into pan

1. Spread the cereal treat mixture into the greased pan and gently press it into an even layer.
2. If you reserved any cookie pieces, sprinkle them over the cereal. 
3. Use buttered fingers to press the cookie pieces into the sticky marshmallow. 
4. Let the pan of treats cool at room temperature for about 1 hour. 
5. Remove from the pan and cut into 16 squares.

printable recipe

Did you make this recipe or have questions? Let me know by leaving a comment and rating the recipe below.

See more cereal treat recipe ideas below the recipe. 

Oreo O's Treats

Beth Klosterboer

Blend melted butter and marshmallows then toss them with Oreo O's Cereal and OREO Cookie pieces to make chewy marshmallow cereal treats.

Print Recipe Pin Recipe

Prep Time 5 mins

Cook Time 10 mins

Cooling 1 hr

Course Dessert

Cuisine American

Servings 16

Calories 197 kcal

Equipment

• 9-inch square pan
• medium-large saucepan
• large mixing bowl
• silicone spatula or wooden spoon

Ingredients

  

• 6 cups OREO O's cereal
• 20 OREO Cookies, broken into pieces
• 4 tablespoons butter
• 10 ounces marshmallows

Instructions

 

• Grease a large mixing bowl, a 9-inch square pan, and a large silicone spatula with butter or baking spray.
• Pour the OREO O's Cereal and OREO Cookie pieces into the large mixing bowl.
• You can reserve some of the cookie pieces to sprinkle over the top of the bars if desired.
• Set aside.
• Begin melting the butter in a medium-large saucepan set over low heat.
• Toss in the marshmallows and stir occasionally until about 75% of the marshmallows have melted.
• Remove the pan from the heat and stir vigorously, smashing the marshmallows, allowing them to melt until smooth.
• Pour the melted marshmallows over the top of the OREO cereal and cookie pieces.
• Toss to coat evenly.
• Gently press the cereal mixture into the prepared pan.
• Sprinkle any reserved cookie pieces over the top if using.
• Let cool for about an hour before cutting into 16 squares.

Notes

• Store your OREO O's Cereal treats in an airtight container at room temperature for up to 5 days.
• Microwave Directions:
• Heat the butter and marshmallows on high power, in a large mixing bowl, for 1 minute.
• Remove and stir vigorously until melted, smashing the marshmallows to help them melt. If needed, heat for additional 15-second increments, stirring vigorously after each, until melted and smooth.
• Pour over cereal then follow the instructions above.

Keyword cereal bars, cereal treats, marshmallows, OREO cereal treats

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