Classic and mini Reese's peanut butter cups are labeled gluten-free. However, seasonal flavors of Reese's peanut butter are not labeled gluten-free as they are manufactured in a different facility. Always be sure to check the label to make sure your peanut butter cups are gluten-free. You can also use Justin's peanut butter cups. The inside of those are a bit softer, so I like to freeze them before adding them in during churning.