To make this Chicken and Biscuits Casserole Recipe gluten-free, use certified gluten-free condensed cream of chicken soup and gluten-free refrigerated or homemade biscuit dough. Confirm that the milk, garlic powder, poultry seasoning, black pepper, frozen peas and carrots, cheddar cheese, cooked chicken, and kosher salt are gluten-free and free from cross-contamination. If using homemade gluten-free biscuits, cut the dough into small pieces and monitor the baking time closely, as gluten-free biscuit dough may bake differently. Prepare the casserole with clean utensils, bowls, cutting boards, and baking dishes to prevent cross-contact with gluten.