Line a baking sheet with parchment paper and set aside.
Combine butterscotch chips and peanut butter in a large microwave safe bowl. Microwave ingredients for 30 seconds, stir and repeat until completely melted.
Add the chow mein noodles to the peanut butter mixture. Stir until combined then add the marshmallows and stir to combine.
Drop by spoonfuls onto the prepared baking sheet.
Let cool at room temperature or place in the refrigerator or freezer to speed up the process.
Notes
STORAGE TIPS
If you store the haystack cookies in an airtight container they will keep for up to a week or longer at room temperature. You can also store them in the refrigerator.You can freeze haystacks, too! If you do, make sure they are fully set and then place them in a freezer-container. For best results, separate them with layers of parchment or wax paper. This will keep them from sticking to each other.
RECIPE VARIATIONS
Add some chocolate chips: You can mix them in after you melt the butterscotch chips. Try semi-sweet chocolate chips, milk, or dark chocolate chips.
Make white chocolate haystacks and swap the butterscotch chips for white chocolate chips.
Add more crunch with some crushed pretzels. Mix them in with the chow mein noodles.
Nuts are great, too! Chopped peanuts, pecans, almonds, or walnuts would work great.
Chopped candy or small chocolate candies are a fun add-in, too. Just make sure the pieces are chopped unless you use something like M&Ms or Reese’s Pieces.
Sprinkles! My kiddos love to add some sprinkles on top of each haystack before they set. This is great for holidays, too – red and green to make them Christmas cookies or other fun colors to match!