- Heat one tablespoon of oil in a large saucepan over a medium-high heat and cook the mince until browned with no pink bits remaining. Remove from the pan and set aside.
- Put the remaining oil into the same pan over a low heat and cook the onion, carrots and celery for 15 minutes until soft.
- Add the garlic, flour and tomato purée. Turn the heat to medium-high and cook for 2-3 minutes, stirring, then return the beef to the pan.
- Add the stock, Worcestershire sauce and herbs. Bring to a simmer and cook, uncovered, for 45 minutes until the gravy is thick. Season well, then add the peas and cook for two minutes. Discard the bay leaf.
TIP: Double or triple the meat mixture and freeze the extra for another day.
- In a large saucepan, cover the potatoes in salted cold water, bring to the boil and simmer until tender. Drain well, then return to the pan and steam dry for 1-2 minutes. Mash with the milk and butter, then season with some salt and pepper.
- Spoon the meat and gravy into an ovenproof dish and carefully spoon over the mash to cover.
TIP: Brush with beaten egg for an extra-golden topping.
- Preheat the oven to 220˚C/200˚C fan/gas mark 7 and cook for 25-30 minutes or until the topping is golden and the pie is bubbling around the edges.