Peanut Butter Marshmallow Squares are a classic no-bake treat that’s sweet, chewy, and irresistibly addictive. With the perfect balance of peanut butter, butterscotch, and soft rainbow marshmallows, these colorful squares are a hit for parties, bake sales, or simply enjoying at home.

Why You’ll Love This Recipe

No baking required — ready with just a few simple steps.
Perfectly chewy with a creamy peanut butter flavor.
Fun rainbow marshmallows add color and sweetness.
Stores well in the fridge or freezer for make-ahead treats.
Great for parties, potlucks, or holiday trays.

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

1 package (300 g) butterscotch chips
1 cup crunchy or creamy peanut butter
1/2 cup butter
1 package (250 g) rainbow miniature marshmallows
1 teaspoon vanilla extract

Directions

Place the bag of marshmallows in the freezer and line an 8×8-inch pan with parchment paper.
In a medium saucepan over low heat, melt the butterscotch chips, peanut butter, and butter, stirring until smooth.
Remove from heat and allow to cool slightly so the marshmallows don’t melt when added.
Quickly fold in the vanilla extract and frozen marshmallows until evenly coated.
Spread the mixture evenly into the prepared pan, using a spatula or spoon to smooth the top.
Refrigerate until firm, about 1 hour.
Remove from the pan, slice into squares, and store in the refrigerator or freezer.

Servings and timing

Servings: About 16 squares
Prep time: 10 minutes
Chill time: 1 hour
Total time: 1 hour 10 minutes

Variations

Use chocolate chips instead of butterscotch for a different flavor.
Swap rainbow marshmallows for plain white mini marshmallows for a more classic look.
Add crushed pretzels or peanuts for extra crunch.
Drizzle melted chocolate over the top for a richer finish.
Use almond butter or sunflower seed butter for a peanut-free option.

Storage/Reheating

Store in an airtight container in the refrigerator for up to 1 week.
For longer storage, freeze for up to 2 months. Place parchment paper between layers to prevent sticking.
No reheating is needed — enjoy them chilled or at room temperature.

FAQs

Do I have to freeze the marshmallows before adding them?

Freezing helps prevent the marshmallows from melting when mixed with the warm peanut butter mixture.

Can I use smooth or crunchy peanut butter?

Either works — crunchy adds texture, while smooth gives a creamier bite.

Can I make these in a larger pan?

Yes, a 9×13-inch pan will work, but the squares will be thinner unless you double the recipe.

Will white chocolate chips work instead of butterscotch?

Yes, but it will result in a sweeter, more vanilla-flavored square.

Can I make these dairy-free?

Use dairy-free butterscotch chips, plant-based butter, and a nut butter of choice.

How do I cut the squares cleanly?

Use a sharp knife and wipe it clean between cuts for neat edges.

Can I use regular marshmallows?

Yes, but cut them into small pieces before adding.

Do these need to be kept refrigerated?

Yes, refrigeration helps them stay firm and fresh.

Can I add mix-ins like coconut or raisins?

Definitely — shredded coconut, dried fruit, or chopped nuts all work well.

Are these suitable for mailing as gifts?

Yes, if shipped in cool weather and packed securely with parchment between layers.

Conclusion

Peanut Butter Marshmallow Squares are the ultimate quick, colorful, and crowd-pleasing dessert. With just a handful of ingredients and no oven required, they’re perfect for last-minute gatherings, holiday treat trays, or an anytime sweet fix. Keep a batch chilled in your fridge or freezer, and you’ll always have a delightful bite ready to share.