Cheese onion & potato pie vote now PreviousNext OtherEasy1 hour Send this recipe to a friend Print this page Ask a question to the author Post your photo of this recipe Ingredients 2 750g potatoes, peeled and quartered 40g butter 1 large onion, thinly sliced 100ml milk 200g mature cheeses, grated (I used a mix of white cheddar, red cheddar and mozza) 1 tsp wholegrain or English mustard (which I subbed with wasabi) ea salt and freshly ground black pepper 2 to 3 tomatoes, sliced * Optional: This is essentially a vegetarian dish but you can add other ingredients too - like leftovers! View the directions