Peanut butter marshmallow squares are a classic treat that comes together in minutes! You only need four ingredients to make these nostalgic no-bake bars! They have the best flavor and texture.

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Watch our step by step video!

No Bake Peanut Butter Marshmallow Squares

Known by probably a dozen different names, these peanut butter marshmallow squares are sweet, salty, amazingly chewy, and delicious. I learned how to make them from Baked By The Lake on Facebook, who lives in Ontario. She said they are so popular that stores frequently sell out of the ingredients to make them during the holiday season. I couldn’t believe how simple these no bake treats came together.

Other names for Peanut Butter Marshmallow Squares

Chocolate Peanut Butter Marshmallow Squares, Stained Glass Bars, Butterscotch Confetti, Confetti Square (again, no s), Butterscotch Surprise, Peanut Butter Bars, Butterscotch Squares, Peanut Butter Fudge, and the list goes on.

In Ontario, they are called “Peanut Butter Marshmallow SQUARE,” no S. I couldn’t deal with that, so I added an ‘s’ at the end of squares. Whatever you call them, they are yummy. I feel like incorporating butterscotch in the name would be a good idea, but it would make the name super long, so I stuck with the original. Here is my version of this classic treat.

Peanut Butter Marshmallow Squares Ingredients

1/2 cup butter (1 stick salted or unsalted butter)
1 bag of butterscotch chips
1 cup creamy peanut butter
1 (16 oz.) bag of mini marshmallows (regular or fruity*)

*These treats are traditionally made with pastel fruity marshmallows. It seems like an odd flavor combination, but that’s how they make them, and they are super popular. With that said, I still decided to make mine with regular marshmallows.

The 4 ingredients above are for the traditional version. I dipped the bottoms of some of mine in milk chocolate—-totally unnecessary but ridiculously good.

How To Customize Marshmallow Butterscotch Bars

There are so many ways to customize these squares. Here are a few!

If you aren’t a fan of butterscotch, use peanut butter chips.
Use half butterscotch chips and half peanut butter chips, or half butterscotch chips and half chocolate chips.
Add a handful of chopped peanuts for crunch.
Sprinkle mini chocolate chips over the tops before they cool.
Drizzle chocolate over cooled bars.
Use a combination of mini marshmallows and Rice Krispies.
Use a combination of mini marshmallows and crunchy chow mein noodles.

How To Make Peanut Butter Marshmallow Bars

Place the bag of mini marshmallows into the freezer while you prep everything else.

Line a 9×13 baking pan with parchment paper.

In a medium saucepan or pot, combine butter, butterscotch chips, and peanut butter. Heat on medium-low heat, stirring, until smooth and creamy. Do not bring it to a boil.

Pour COLD marshmallows into a large bowl. Pour the smooth peanut butter mixture over the marshmallows.

Stir until completely coated.

Pour into prepared pan and pat with a rubber spatula to evenly distribute.

Chill in the refrigerator for 1-2 hours.

Cut into 24 squares.

Chocolate Dipped Peanut Butter Squares

To take them up a notch, dip the squares in melted chocolate chips or Ghirardelli chocolate melts. Let excess drip off (I find that dragging it across the edge of the bowl helps), then place on a parchment-lined baking sheet to set.

You can store the bars at room temperature, in the refrigerator, or in the freezer. We like them chilled, but they are delicious no matter how you store them. If stored in an airtight container, they will stay fresh for up to 7 days, making them perfect for bake sales or to add to Christmas treat plates.

Peanut Butter Marshmallow Squares Recipe