Line a 9x13 baking pan with parchment paper. Set it aside.
Place the mini marshmallows into the freezer. They need to be in the freezer for 20-30 minutes, while you prep everything else. 16 oz Mini Marshmallows
Add the butterscotch chips, peanut butter, and butter to a medium sauce pan. Heat over medium low, stirring occasionally until everything is melted and the whole mixture is creamy. 11 oz Butterscotch Chips, 1 cup Creamy Peanut Butter, 1/2 cup Unsalted Butter,
Remove the mixture from the heat and stir in the vanilla extract, and salt. Let it sit for about 10 minutes, while the marshmallows are still chilling. 1 tsp Vanilla Extract, 1/2 tsp Salt
Pour the cold marshmallows into the pot with the peanut butter mixture. Gently fold the mixture over the top of the marshmallows until they are completely coated in it.
Pour the mixture into the prepared baking pan. Spread it to the edges and corners evenly.
Let the bars sit at room temperature for a couple hours, or in the fridge for about 1 hour until the butterscotch mixture is set.
Cut into squares and enjoy.