Cheesy celeriac, potato & bacon pie

Method

• step 1

  Heat oven to 200C/180C fan/gas 6. Put the celeriac and potatoes in a large pan, cover with salted water and bring to the boil. Turn down the heat and simmer until just tender, about 5 mins. Drain, then toss with the cream, rosemary and seasoning. Set aside.

• step 2

  Roll one of the blocks of pastry until just bigger than a large dinner plate, cut into a neat circle and place onto a flat baking sheet. Leaving a 3cm border, spread out a layer of celeriac and potatoes, top with some cheese and bacon, then repeat the layers until all the ingredients are piled up.

• step 3

  Roll out the second block of pastry large enough to completely cover the bottom sheet and filling with some overhang. Brush the bottom border with a little of the egg, then drape the pastry sheet over, pushing down to seal the edges. Trim off the excess with a sharp knife and crimp edge together with a fork. Can be made a day ahead and chilled before baking or frozen for up to 1 month. Defrost completely before baking.

• step 4

  Pierce a steam hole in the top of the pie, brush all over with remaining egg and score the pastry lightly with spoke marks, if you like. Bake for 25 mins until golden brown. Stand for 5 mins before serving.