Heat oven to 200C/fan 180C/gas 6. Heat oil in a large
pan, then cook the onion, garlic and chilli for 2-3 mins
until tender. Stir in the garam masala, turmeric and
cumin, then cook for a further 2-3 mins.
Add carrots, parsnip, cauliflower and courgette to the
pan with 300ml/1/2pt water, bring to the boil, then simmer
for 5 mins until the vegetables are almost tender. Drain,
reserving the cooking liquid, then mix with the peas.
Melt butter in a small pan, stir in flour, then cook for
1 min. Add reserved vegetable cooking liquid, then cook,
stirring, until it forms a thick sauce. Simmer for 3 mins,
stirring, then remove from heat and stir in the yogurt,
coriander, vegetables and seasoning. Leave to cool.
Spoon the mixture into a 900ml pie dish. Brush the rim
of the dish with water. Roll out pastry and use to cover
the pie, pressing firmly on to the rim. Trim edges and
press firmly to seal. Make a hole in the centre of the pie
to allow steam to escape. Brush with the milk, place on
a baking sheet and bake for 25-30 mins.