This is a decadent, savoury French gratin made with potatoes, salty bacon lardons, onions, and plenty of cheese. It’s creamy yet crunchy, making it a perfect comfort dish. 
It is traditionally made with Reblochon, but you can use any other firm washed-rind cheese or any pungent melting cheese like Fontina or Raclette.
Preparation time: 20 minutes
Cooking time: 1 hour
Serves: 6
Ingredients
1.2kg new/waxy potatoes, we used Charlotte
250g smoked bacon lardons or diced pancetta
1 large onion, finely sliced
175ml white wine
1 garlic clove, crushed
200ml crème fraiche
400g Reblochon cheese (or substitute), chopped into 2cm pieces
Method
– Bring a large pan of water to the boil and cook the potatoes for 15-20min, until just tender. Drain well, rinse briefly under cold water and set aside to cool.
– Fry the lardons over a medium heat until they are beginning to turn golden. Using a slotted spoon, lift them into a bowl, leaving any fat behind.
– Add the onions and a pinch of salt to the pan, lower the heat and cook gently for 10 minutes, until softened. Turn up the heat and cook until the onions are become golden.
– Return the lardons to the pan along with the wine and garlic. Bring to the boil and allow to reduce until most of the liquid has evaporated (about 5 minutes). Set aside to cool to room temperature, then stir in the crème fraîche and add some seasoning.
– Preheat oven to 200°C (180°C fan) gas mark 6. Slice the cooled potatoes into bite-size pieces, then transfer half of the slices to the base of a 2.5-3 litre ovenproof casserole dish.
– Spoon over half the crème fraîche mixture, followed by half the cheese. Repeat the layers to use up the other half of the ingredients.
– Cook in the oven for 20-25min, or until golden and bubbling. Leave to rest for 5min before serving with a green salad.
