"Create a recipe for Beef & Pork Burgers with Caramelized Onion Mayonnaise, adapted for a household of 3 and beginner cook. Use imperial units only. Keep it quick and easy where possible, but preserve the core idea: beef and pork burger patties, caramelized onion mayonnaise, and melted cheese on buns. Ensure the recipe avoids gluten, dairy, nuts, shellfish, and corn. Use minimal processing, moderate budget, and low-inflammation-friendly ingredients. Include clear ingredients, concise step-by-step instructions, prep/cook times, and servings. If buns are included, make them gluten-free and corn-free, or suggest lettuce wraps if needed. Avoid any prohibited ingredients."