You can make one big pie if you prefer. Use
a 1.2-litre pie dish and increase the cooking
time in the oven by about 10 minutes.
Heat oven to 200C/fan 180C/gas 6. Chop
the parsnips and potatoes into chunks, then
boil for 15 mins until tender. Drain, reserving
the water, then mash with a little seasoning.
Cut chicken into small chunks, then toss in
the cornflour. Heat the oil in a large pan, add
the leeks, then fry for 3 mins until starting to
soften. Add the chicken and 200ml water
from the potatoes, then bring to the boil,
stirring. Reduce the heat, then gently simmer
for 10 mins, until the chicken is just tender.
Remove from the heat, then stir in the lemon
zest, parsley, crème fraîche and mustard.
Divide the chicken filling between four 300ml
pie dishes. Spoon over the mash and spread
roughly with a fork to seal in the filling. Bake for
25 mins until the topping is crisp and golden.