No-Bake Peanut Butter Marshmallow Cereal Bars

These bars are a hybrid of some of my favorite bars.

No-bake, ChewyGooey, Caramely, with Peanut Butter, Special K, Cereal, Marshmallows.

And they’re so good. And so easy.

Ever since I made the Chewy Peanut Butter and Chocolate Cereal Bars, I’ve been thinking about how to remake them in a slightly new way.

These bars are based heavily on those, but instead of using Rice Krispies, I used Special K. You could also use Corn Flakes, Frosted Flakes, Rice Krispies, or a similar vegan or gluten-free cereal.

Instead of topping them with chocolate-peanut butter swirls, I stirred in marshmallows. I love marshmallows in bars because they lend so much gooey-and-chewy texture.

Plus, marshmallows are more well-behaved in the Caribbean heat and don’t melt everywhere like chocolate.

No-bake bars like these are always nice so you don’t have to heat up your house, especially this time of year.

And they’re made in one bowl in the microwave, and take less than 5 minutes to stir together. Usually it’s the fast and easy recipes people seem to make anyway, and you can add this one to the Fast and Easy list.

There’s no butter in the recipe, but you’d never guess it because they’re exceedingly buttery-tasting and rich.

The microwave-made sauce drenches the cereal in a sweet, brown sugary, caramel-vanilla, peanut buttery syrup and holds the bars together.

I love bars that I can really sink my teeth into, and these deliver.

They’re dense, wonderfully soft, with tons of chewiness and texture from the cereal and marshmallows.

Peanut butter has a way of making everything taste so good and decadent.

Even Special K.

Yield: one 8-by-8-inch pan, 9 to 12 squares

No-Bake Peanut Butter Marshmallow Cereal Bars

Prep Time 5 minutes
Cook Time 2 minutes
Additional Time 1 hour 53 minutes
Total Time 2 hours

These fast, easy, no-bake bars are a hybrid of some of my favorite bars, which include peanut butter, marshmallows, cereal and are held together with a brown sugar-caramel sauce that’s made in the micro in 1 bowl. They’re dense, wonderfully soft, with plenty of chewiness and texture and you can really sink your teeth into them. There’s no butter in the recipe, but you won’t miss it because the bars are rich and very buttery tasting.


  • 1 heaping cup creamy peanut butter (use Jif, Skippy, or similar; do not use natural or homemade peanut butter)
  • 1/2 cup light corn syrup (light colored, not lite)
  • 1/2 cup granulated sugar
  • 1/4 cup light brown sugar, packed
  • 1 tablespoon vanilla extract
  • 3 1/2 cups Special K cereal (Corn Flakes may be subsituted, or use about 3 cups Rice Krispies cereal)
  • about 5 ounces marshmallows (half of one standard bag; I used large but mini are ideal)


  1. Line an 8-inch square pan with aluminum foil leaving overhang, spray with cooking spray; set aside.
  2. In a large microwave-safe bowl, combine 1 heaping cup peanut butter, corn syrup, sugars, and heat on high power for 1 minute to melt.
  3. Stop to stir. Mixture will be on the granular side, this is okay.
  4. Return bowl to microwave and heat for 1 more minute on high power.
  5. Stir in the vanilla.
  6. Stir in the cereal and marshmallows. The marshmallows will melt to some extent, but not fully.
  7. Turn mixture out into prepared pan, packing it down somewhat firmly with a spatula, and smooth the top.
  8. Cover pan with a sheet of foil (to prevent fridge smells), and place pan in fridge to set up for about 2 hours or until set, before lifting out with foil overhang, slicing, and serving.
  9. Bars will keep airtight at room temperature for up to 1 week, in the refrigerator for up to 2 weeks, or in the freezer for up to 6 months.

Adapted from Chewy Peanut Butter and Chocolate Cereal Bars

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 288Total Fat: 11gSaturated Fat: 2gTrans Fat: 0gUnsaturated Fat: 7gCholesterol: 0mgSodium: 182mgCarbohydrates: 45gFiber: 1gSugar: 32gProtein: 7g

Related Recipes:

Chewy Peanut Butter and Chocolate Cereal Bars (no-bake, vegan, GF)

Peanut Chewy Payday Bars (almost no-bake)

Caramel and Chocolate Gooey Bars

Double Chocolate Caramel Corn & Cocoa Rice Krispies Candy Bars

Nutella and Peanut Butter Graham Bars with Chocolate Frosting

Browned Butter Rice Krispies Treats – The best RKTs I have ever had. Double the butter and it’s browned, for great flavor and soft, buttery, chewy bars

Special K Bars


No-Bake Nutter Butter Special K Bars

Peanut Butter Caramel Twix Bars (almost no-bake)

Peanut Butter Chocolate Chunk Cookie Bars

Nutella-Swirled Peanut Butter Chip Blondies

Biscoff Marshmallow Chocolate Bars

Marshmallow Caramel Oreo Cookie S’Mores Bars

 Thanks for the entries in the 3-Piece Baking Set and Gluten-Free Dough Giveaway and the $100 My Sweet Muffin Giveaway

What’s your favorite no-bake or fast and easy dessert?