Tartiflette tart

Method

• step 1

  Put the butter and a mixing or food processor bowl into the freezer 1 hour before making the pastry.

• step 2

  To make the pastry, pulse the butter, flour and salt in a food processor until it resembles breadcrumbs. Alternatively, tip into a bowl and use your fingertips to rub together until it resembles breadcrumbs. Add one of the egg yolks and 2-3 tbsp of ice-cold water, and mix until it comes together as a dough, being careful not to over-mix. Wrap and chill for 30 minutes.

• step 3

  Roll out the pastry to the thickness of a £1 coin and line a 22cm loose-bottomed tart tin. Prick the base all over with a fork. Chill for 20 minutes.

• step 4

  Heat the oven to 200C/fan 180C/gas 6. Line the pastry shell with baking paper, fill with baking beans and blind bake for 20 minutes.

• step 5

  Remove the beans and baking paper, and return the pastry shell to the oven for 10 minutes, then brush the base all over with the other egg yolk (whisk it first) and bake for a further 2 minutes. Cool.

• step 6

  Cook the lardons in a frying pan for 5 minutes until the fat has rendered and become crisp. Scoop out onto a plate and add the onions and a pinch of salt to the pan. Gently cook for 40 minutes until sticky and caramelised. Add the white wine and bubble until it evaporates, then add the double cream and cook until thickened. Stir through the lardons.

• step 7

  Heat the oven to 180C/fan 160C/gas 4. Gently tip the potatoes into the pastry case, then pour over 1/2 the bacon and onion mixture. Layer on 1/2 the reblochon, then sprinkle over the pickled onions and cornichons. Pour over the remaining bacon and onion mixture, then top with the remaining reblochon. Bake for 15 minutes until bubbling. Serve with a green salad, if you like.