A simply tart layered with sliced potato and onion, served with dollops of crème fraîche. To make this vegetarian just leave out the bacon. Put some sautéed mushrooms on top, or slices of a melting cheese, such as taleggio.
- 500g ready-made puff pastry, butter puff is best
- 2 large onions, thinly sliced
- 25g butter
- 500g waxy potatoes
- 300g smoked bacon lardons
- 125g crème fraîche
- ½ tbsp chopped parsley (optional)
Roll out the pastry to make a 35.5cm circle and put it on a lightly floured baking-sheet. Prick all over with a fork. Put a circle of greaseproof paper on top (measuring about 6cm less than the pastry) and weigh it down with baking beans.
Put into an oven preheated to 190C/gas mark 5 and cook for 20 minutes, removing the paper and beans after 15 minutes.
The pastry will billow up despite the beans, but just press it down with the back of a wooden spoon when you remove it from the oven. Set the pastry aside.
Sauté the onions in 15g of the butter over a very low heat with a splash of water until golden and soft (it will take about 15 minutes). Keep an eye on them to make sure they don’t catch at the bottom of the pan. Season.
Peel then parboil the potatoes for about 10 minutes and, when they’re cool enough to handle, slice very thinly. Melt the remaining butter.
Put the onions on to the cooked pastry using a slotted spoon, leaving a 3cm border all the way round. Then lay the potatoes on top, brushing with butter and seasoning as you go.
Turn the oven up to 200C/gas mark 6, and cook the tart for 15 to 20 minutes, or until the top is golden. Fry the lardons in the onion pan until they’re golden brown.
When the tart has five minutes’ cooking time remaining put the lardons and teaspoonfuls of the crème fraîche all over it. Return to the oven to finish cooking.
Sprinkle with parsley, if using, and serve.