Preheat oven to 200°C and grease a 9cm x 19cm loaf pan. (Note: Size/number of dishes required will change if you increase the yield of the recipe)
Heat oil in a medium frying pan over medium heat, add onion and garlic and cook, stirring occasionally, until onion has softened (approximately 5 minutes). Set aside to cool.
Place onion, breadcrumbs, mince, egg, mustard and tomato sauce in a bowl, combine and spoon into pan, making sure to smooth out the top.
Bake for 45 minutes, top with cheese and return to the oven until the meatloaf comes away from sides of pan (approximately 15 minutes). Drain juices from pan and set aside for 5 minutes.
Serve with potato, green beans and gravy.