To make this recipe gluten-free, use a certified gluten-free onion soup mix, as many packaged soup mixes may contain wheat or gluten-based additives.
Verify that the beef broth is labeled gluten-free, especially if using packaged or canned broth.
Use plain, unseasoned beef stew meat to avoid hidden gluten in marinades or seasoning blends.
Check all additional toppings, such as shredded cheese, sour cream, bacon, or chives, to ensure they are gluten-free.
Prepare the recipe with clean utensils, cutting boards, and slow cooker equipment to prevent cross-contamination.