"Create a dairy-free, wheat-free, corn-free, from-scratch version of a dump-and-bake meatball casserole inspired by the linked recipe. Make it beginner-friendly, quick and easy (15-30 minutes active time), minimal processing, low-inflammation friendly, and suitable for a household of 3. Use only safe ingredients that avoid gluten, dairy, nuts, shellfish, soy, sesame, and corn. Include homemade meatballs from scratch, a simple sauce from scratch, and a casserole-style baked pasta dish. Use imperial units only. Keep the recipe practical for an oven/stovetop beginner cook."