Butterscotch Peanut Butter Marshmallow Squares

These classic Butterscotch Peanut Butter Marshmallow Squares are one of my favourite nostalgic childhood treats. Creamy peanut butter and butterscotch chips give way to squishy rainbow-coloured marshmallows in these beloved old-fashioned fudge-like squares. 

peanut butter marshmallow bars cut into squares on a sheet

An informal poll of in my Instagram story revealed that 70% of you aren’t familiar with these delicious treats. That tells me they might be a Canadian thing. Creamy peanut butter butterscotch squares, plump with coloured marshmallows, were on every cookie plate I ever was offered as a kid. You need them in your life.

An Easy, No-Bake Peanut Butter Marshmallow Square Recipe

All you need to make these scrumptious bars is a microwave-safe large measuring cup or bowl and a baking pan.

Add peanut butter, butter, and butterscotch chips to the bowl, give them a gentle melt, then pour them over the marshmallows in the pan.

Lining the pan with parchment paper makes for the easiest lifting out and clean-up.

peanut butter marshmallow butterscotch treats cut into strips

Tips for the Best Butterscotch Peanut Butter Marshmallow Squares

Not only does refrigerating them help them firm up faster so you can eat them faster, I’d argue that peanut butter butterscotch bars taste better cold. There’s something about a chewy, cold marshmallow against a creamy peanut butter base that really gets me.

I actually employ the chill at two stages. Before I even start the recipe, I toss the bag of marshmallows in the freezer. This ensures they don’t melt when the warm peanut butter-butterscotch mixture hits them.

Despite using white mini marshmallows in these pictures, I actually really love these bars with coloured variety. Use a tasty peanut butter. Not the gritty kind you grind yourself at the grocery store that has no salt and uses (semi-rancid) unroasted peanuts. I actually prefer salted in this recipe. It adds a nice contrast to the sweet butterscotch.

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Peanut Butter Marshmallow Butterscotch Squares

Prep Time 5 minutes
Cook Time 3 minutes
Servings 24


  • 1 300-g bag butterscotch chips
  • 1 cup creamy peanut butter
  • ½ cup butter
  • 4 cups mini marshmallows (white or coloured)


  • Combine butterscotch chips, peanut butter and butter in a large microwave-safe dish. Microwave on 50% power for 2 minutes. Remove, stir, then microwave another 1 minute on 50% power. Cool slightly.
  • Line a 8x8" square baking pan with parchment paper. Add the marshmallows. When butterscotch mixture has cooled slightly, pour over marshmallows and stir to combine and spread evenly in pan. Refrigerate until firm, about 1 hour. 

Last Updated on December 15, 2018 by Jennifer Pallian BSc, RD

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