Potato pie

Method

1. 1 Roll out a round Buitoni pastry sheet.
2. 2 Make a layer of potatoes sliced very thinly with the mandoline.
3. 3 In a frying pan cook the onion, the sliced pancetta and a few potatoes cut into julienne.
4. 4 Leave to cool, add an egg, stir and spread it as a layer over the bed of potatoes.
5. 5 Add another layer of very thin potato slices and a few knobs of butter, then fold the edges over the potato layer.
6. 6 Bake at 140 degrees with bottom heat only for about forty minutes and then about fifteen minutes under the grill to get a crisp crust