There are loads of recipes on the internet but most of them are over the top. I tend not to give out all recipes as I alter them so much but here it is, in its simplest form.
1 medium onion finely diced
1lb ground/minced beef (or pork or a combination of the two)
1 1/2 pints meat stock (two stock cubes)
1 tablespoon tomato puree
1 1/2 lb chunks of peeled potatoes
Grated strong cheese - I use cheddar
Add two tablespoons of oil into a frying pan and fry the onion until soft but not brown - remove from pan.
Add the meat and fry until no longer pink. Try not to stir it all the time so it can develop some crispy brown bits, but this isn't essential. Fry until any liquid that comes from the meat evaporates off. Stir the onion back in.
Add the stock, bring to a boil, turn down to a simmer and put a lid on the pan. Cook for about 30 minutes. Thicken either with cornflour and water or gravy granules to your preferred thickness.
Most people don't do this next part but I prefer to. Tip the contents of the pan through a strainer, sieve or colander, KEEPING all the liquid. Tip the drained meat into your cooking dish/dishes. A lasagne type dish works well or two smaller dishes. Leave to go cold.
Cook the potatoes until done. Drain and mash with salt and pepper, a little milk and butter/margarine. Place in spoonsfuls on top of the meat and carefully spread over to cover the meat. Top with as much cheese as you wish.
Bake in a 190C - 200C oven for about 30 - 40 minutes or until bubbling slightly and the cheese has melted and going slightly crispy.
Warm the rest of the gravy you strained off earlier towards the end of cooking. Serve as is or with your chosen vegetables.
We rarely have all meat in ours. Most of the time we will use 1/2 lb meat and lots of diced vegetables. Sometimes I top the potato with a bag of smashed hula hoops to give a crunch topping. If I have no fresh potatoes I will use instant. Measure out a 6 person serving into a large bowl. Add the required liquid but use half milk and half water, add about 1oz of butter and some black pepper.
Also, if you have leftover meat, vegetables and gravy from a roast, mince that and use, remembering to add a few spoonfuls of the gravy into the meat/vegetable mix otherwise it will be too dry
Hope that helps.