675g floury potatoes, peeled and cut into medium chunks
100ml milk or single cream
75g grated Cheddar
Heat the oil in a large pan and cook the onion and carrot until soft but not coloured.
Add the mince and cook for 5 minutes until brown on a moderate heat, turning frequently and mashing any large lumps with the back of a wooden spoon. Remove and discard half the oil. Stir in the peas.
Stir in the flour and cook for 1-2 minutes, then add the ketchup, yeast extract, Worcestershire sauce, rosemary, lamb stock cube and water. Season. Bring to the boil, reduce the heat and simmer gently for 20 minutes.
Meanwhile prepare the potatoes for the topping. Place the potatoes in a large saucepan and bring to the boil. Reduce the heat, cover and simmer for 20-25 minutes. Drain the mash together with the milk or cream and butter. Season and stir in the cheese.
Preheat the oven to 160-170°C fan, 180-190°C, gas mark 4-5.
Spoon the meat filling into individual ovenproof dishes and pipe or spread the surface with the potato mixture. Run a fork across the top of the mash. Bake uncovered for 30 minutes, or until the top is brown.