Bring a large pot of water to a boil. Add the egg noodles and cook until tender, about 8 minutes. Meanwhile, crumble the beef mince and pork into a large frypan over medium heat. Add the onion to the meat once there are juices in the pan. Cook and stir until onion is tender and meat is no longer pink. Drain grease.
Transfer the meat and onion to a 20x30cm baking dish and mix in the egg noodles, cheese, tomato passata, corn, green capsicum and mushrooms.
Bake for 45 minutes in the preheated oven, until bubbling hot and lightly browned on the top.