Short description

These Rainbow Marshmallow Bars are delightfully chewy and colorful dessert treats made with layers of soft marshmallows, buttery crispy cereal, and a burst of rainbow. They combine rich texture, sweet flavor, and vibrant colors to make a fun and delicious snack or dessert bar.

Why You’ll Love This Recipe

Eye-catching and festive—perfect for parties, bake sales, or sprinkling joy into everyday life.
Simple ingredients, minimal equipment, and straightforward steps.
Textural contrast: a crisp cereal base meets gooey marshmallow and crunchy sprinkles.
No baking required—quick to assemble and quick to enjoy.

ingredients

(Tip: You can find the complete list of ingredients and their measurements in the recipe card below.)

crispy rice cereal
mini marshmallows
unsalted butter
vanilla extract
rainbow sprinkles
salt

directions

Grease a square baking pan or line it with parchment paper to allow easy removal.
In a large saucepan over medium heat, melt the butter until fully liquid and slightly bubbling. Be careful not to brown.
Add the marshmallows to the melted butter and stir gently until they are completely melted and smooth. Remove from heat.
Stir in vanilla extract and a pinch of salt to balance sweetness.
Fold in the crispy rice cereal until all pieces are evenly coated with the marshmallow mixture.
Quickly transfer half of the marshmallow‑cereal mix into the prepared pan and press lightly to form the first layer.
Add rainbow sprinkles across the top of this layer. Sprinkle generously so color shows.
Pour the remaining marshmallow‑cereal mixture over the sprinkles and press gently to seal and level the top.
Allow to cool at room temperature until set, about 1‑2 hours (or refrigerate for faster setting).
Once firm, remove from pan and cut into bars or squares with a sharp knife.

Servings and timing

Makes: about 16 bars (depending on size)
Preparation time: 15 minutes
Cooling/setting time: 1–2 hours
Total time: approximately 1 hour 15 minutes to 1 hour 30 minutes

Variations

Chocolate drizzle: Drizzle melted dark or white chocolate over the top for a decorative finish.
Flavored marshmallows: Use flavored marshmallows (e.g. strawberry, vanilla swirl) to add a twist.
Cereal swap: Try using Fruity Pebbles, cornflakes, or Cocoa Krispies instead of plain crispy rice for different flavors and textures.
Add nuts or dried fruit: Fold in chopped nuts or dried fruit for extra chew and crunch.
Themed sprinkles: Use seasonal sprinkles (holiday, stars, hearts) to match occasions.

storage/reheating

Store bars in an airtight container at room temperature for up to 3 days.
To keep them from sticking together, place sheets of parchment paper between layers.
For longer storage, you may refrigerate; they will last up to 1 week, though texture may become slightly firmer.
These bars are not suited for reheating; marshmallow base will soften when warm. If too firm, let them sit at room temperature for a bit before serving.

FAQs

What type of marshmallows work best?

Mini marshmallows melt more quickly and evenly, giving a smoother texture. If using regular‑sized marshmallows, cut them into smaller pieces to ensure even melting.

Can I make these bars gluten‑free?

Yes. Use a gluten‑free crispy rice cereal and verify that all ingredients (like sprinkles) are labeled gluten‑free.

How do I prevent the bars from sticking to the pan?

Line the pan with parchment paper with some overhang, or grease it well with butter or nonstick spray. This helps lift out the set bars cleanly.

Can I reduce the sweetness?

You can slightly reduce sweetness by using fewer marshmallows or by adding a small amount of unsweetened puffed grain to balance. Or choose darker chocolate drizzle rather than white.

Why are my bars too sticky or soft?

This can happen if marshmallows weren’t fully cooled/firmed before cutting or if the ratio of marshmallow to cereal is high. Cooling longer helps, or add a bit more cereal.

Can I freeze the bars?

Yes, you can freeze these. Wrap individual bars in plastic wrap and store in an airtight container or freezer bag. They can keep frozen for up to 2 months. Thaw in refrigerator or at room temperature before eating.

How thick should I press the bars in the pan?

Press them to a uniform thickness so that they set evenly. About 1‑inch thick is typical; too thick and they may be difficult to cut, too thin and they could crumble.

Do sprinkles melt or bleed color?

Most sprinkles hold their color fairly well in this recipe since the marshmallow temperature is moderate. To avoid bleeding or fading, give the bottom layer a head start to set slightly before adding sprinkles.

Can I make them ahead for a party?

Yes. They are ideal for preparation a day ahead. Store in a sealed container to maintain freshness. If decorated or with drizzle, add that just before serving so it looks its best.

Is it possible to reheat or soften hardened bars?

If bars become overly firm (e.g. after refrigeration), leave them at room temperature for 30 minutes before serving. Avoid applying heat directly, as that may melt the marshmallow unevenly.

Conclusion

Rainbow Marshmallow Bars are a joyful and easy dessert perfect for adding a pop of color and sweetness to any occasion. With simple ingredients and no baking required, you can whip them up in little time and enjoy chewy, marshmallowy goodness with a satisfying crunch. Whether making them for friends, family, or just because, these bars are sure to delight.