Meat and Potato Casserole

Ingredients

• 1 lb. (450 g) lean beef, diced
• 2 cups (500 g) prepared mashed potatoes
• 1 (10.75 oz. or 300 g) can condensed cream of mushroom soup
• 1 medium (3.5 oz or 100 g) white onion, chopped
• 3/4 cup (6.6 fl oz or 185 ml) fresh milk
• 1/4 cup (1 oz or 30 g) parmesan cheese, finely grated
• sea salt and freshly ground black pepper, to taste
• 1/2 cup (55 g) cheddar cheese, shredded