To make these Double Chocolate Marshmallow Treats gluten free, use a certified gluten-free crisp rice cereal, since many standard crisp rice cereals contain malt or other gluten ingredients. Also confirm that the mini marshmallows, cocoa powder, bittersweet chocolate, and any optional toppings such as crushed peanuts are labeled gluten free, as brands and manufacturing practices can vary. For anyone with celiac disease or severe gluten sensitivity, use clean pans, parchment, spatulas, saucepans, and cutting tools to avoid cross-contact.