For the sauce, heat the oil in a pan and add the onion. Cook until soft, add the garlic, ginger and curry powder, then cook until aromatic. Turn up the heat, add the mince, fry until browned, then add the tomatoes and simmer for 20 mins until thickened. A few mins before the end, add the peas.
Meanwhile, tip the parsnips and potatoes into a pan of cold water, bring to the boil, then cook for 10 mins. Drain, season and mash with the rest of the ingredients.
Heat oven to 220C/fan 200C/gas 8. Assemble the pies in individual dishes (or one large one) by placing some meat sauce
on the bottom and topping with mash. Ruffle up the tops with a fork, then bake for 20 mins until golden and bubbling.