Step 1:
1. Thinly slice potatoes and add to saucepan of water. Boil until softened. Step 3:
2. Cube the onion and place in saucepan with potatoes. Add the milk, cover saucepan and bring to the boil. Step 5:
3. Simmer for 3 mins then drain. Butter an ovenproof dish and layer half of the potatoes (so they overlap) in it. Sprinkle half of the onions on top then season with salt & pepper.Sprinkle cheese on top. Step 7:
4. Layer the remaining potato on top. Add rest of the onion and cheese. Season again with salt & black pepper. Step 9:
5. Bake at 190c for 35mins or until crispy and golden.