Rather than provide lots of separate recipes, it might be best to give them some really simple
guidelines. Here's an example of what you might say:
"Casseroles are really easy. You just need something to cook (such as sausages, pork chops, chicken breasts or whatever you like) and something to cook it in. You don't need to buy expensive 'cook in' sauces; just use soup, dry cider, baked beans or whatever else you think goes best with what you're cooking. 40 minutes at Gas Mark 5 (190C) is usually good enough for most casseroles but it's almost impossible to casserole something for too long, so don't worry about it.
For example, sausage and bean casserole is rather tasty. At it's simplest, you empty a can of baked beans into a casserole dish, add the sausages and put it in the oven to cook. If you'd like it a little spicier, just add a bit of chili powder or paprika. If you want a beefier flavour, just make up some instant gravy and put that in.
If you want to casserole chicken breasts, perhaps mushroom soup would be a good thing to cook them in; you can add some sliced mushrooms if you like.
If it's pork chops, then perhaps dry cider would be a good idea, possibly adding some sliced vegetables.
So you don't need any recipes; you just need ideas!"
Then all you need to do is to check that they can microwave jacket potatoes and cook both rice and pasta and they're well on their way to producing lots of different meals, perhaps by following my guidelines here:
http://www.theanswerbank.co.uk/Food-and-Drink/Question1107850.html#answer-6694405
Chris