Peanut Butter Squares

1/2 cup butter
1 cup peanut butter
1 (300g pkg.) butterscotch chips
1 tsp. vanilla (optional)
1 (250g) pkg. mini marshmallows (I prefer colored)

Melt butter over medium heat.

Add peanut butter and butterscotch chips; stir until melted. Add vanilla.

Remove from heat and add marshmallows stirring until coated.

Pour into pan and refrigerate until set.