Step 1: In a large mixing bowl, combine the chow mein noodles, peanuts (if using), and mini marshmallows (if using). Gently toss to distribute the ingredients evenly.

Step 2: Over low heat, in a medium saucepan, combine the creamy peanut butter and butterscotch chips. Stir continuously until smooth and well blended.

Step 3: Pour the melted butterscotch and peanut butter mixture over the chow mein. Use a spatula or wooden spoon to gently fold and mix until all the noodles are uniformly coated.

Step 4: Line a baking sheet or tray with parchment paper. Drop spoonfuls of the mixture onto the parchment paper or use your hands to shape them into small haystack-like mounds.

Step 5: Allow the haystacks to cool at room temperature for at least 30 minutes to 1 hour until they are set and no longer collapse.

Step 6: Once the haystacks have reached the desired consistency, they are ready to be enjoyed. You can store them in an airtight container, where they will stay fresh for up to a week, but they are likely to be devoured before then!