Step 1

Preheat oven to 180C. Grease a medium oven-proof dish.

Step 2

Peel potatoes and slice thinly. Place in a saucepan and cover with water. Bring to the boil and simmer for 5 minutes, then strain. Meanwhile, heat oil in a frypan and cook onion and bacon for 5 minutes until onion is soft. Drain on paper towel.

Step 3

In the saucepan you used to cook the potatoes, melt butter and whisk in flour. Allow to cook for 1 minutes, then whisk in stock. Bring to the boil, then remove from heat.

Step 4

Combine potatoes, bacon and onion mixture and stock mixture and place in prepared oven-proof dish. Cover with foil and bake for 30 minutes. Remove foil, sprinkle over cheese, and return to oven for a further 10-15 minutes until golden and bubbly.