Weigh out all ingredients and dice vegetables into small chunks.
Heat a large pan and fry the mince until browned. Put oil into the pan, add the vegetables and cook on a gentle heat until soft for about 20 minutes.
Add the garlic, flour and tomato purée, increase the heat and cook for a few minutes, then return the beef to the pan and add the stock, Worcestershire sauce and herbs.
Bring to a simmer and cook, uncovered, for 45 minutes. By this time the sauce should be thick and coating the meat.
Check after about 30 minutes – if a lot of liquid remains, increase the heat slightly to reduce the sauce a little more. Remove the bay leaves and thyme stalks.
Meanwhile, make the mash. Using a steamer over boiling water (or a pan with just enough water to cover potatoes) cover and cook for approx. 15 -20 minutes.
Mash well with the milk, butter, and three-quarters of the cheese, then season with the nutmeg.
At this point take out the amount for baby and blend for a few seconds to give it a slightly softer texture. You can add potato after.
Spoon the rest of the meat into ovenproof dishes, leave meat to cool as this stops potato sinking when spread on top. Preheat your oven to 220C/200C fan/gas 7.
Pipe or spoon on the mash to cover and sprinkle with the remaining cheese.
Put in the oven to cook for 25 to 30 mins, or until golden.