Hmm, going to have to think, haven't made a casserole in a while.
I chop onions and garlic and saute in olive oil. Add a tablespoon or two of tomato paste and cook for a minute or two, then set aside. Cute round steak into cubes, dust in flour and brown with a little more olive oil. Might need to do in a couple of batches (500 gr steak for a medium size cassesrole, 1 kg for a larger casserole that will give you enough left-overs to make beef pies the next day
Add onion mix back to browned steak, add stock (vegie or beef stock ) and water just to cover. If I have (a decent) dry red wine, I will add that first and cook off, before I add the stock and water. Throw in whatever vegies I have: chopped carrots, swedes, zucchini, etc. Mushrooms are always good. Chopped bacon adds a lovely flavour. Some herbs (I use what I have in the garden: rosemary, thyme) and a bay leaf. Turn the heat down low and let it simmer for a couple of hours/or put in oven for a couple of hours. Or I put it into the slow cooker and let it bubble away all day - much better option in warmer weather.
The left overs the next day are the best bit, when used with a bit of puff pastry for a quick and easy beef pie.