Well both can help with planning and the elder one with cooking.
Soups, back of the fridge soup, stem soup (the stems of veg like broccoli and cauliflower). I use my slow cooker, I just chop and throw things in and then when I want to eat I use a stick blender.
Rice dishes
Kedgeree, probably best to make it a mild one, paella - well I'm saying that what I mean is a dish of rice with spices and chicken added. I make a smoked haddock and rice both cooked in a mix of water and orange juice.
Tray bakes of various types.
Stuffed things, peppers, aubergine, courgettes (you can use the left over rice dishes as long as you cool the rice quickly and keep in the fridge).
Home made chicken nuggets / goujons. Buy chicken mini fillets (or what ever boneless chicken is cheapest) a bowl of flour, one of beaten eggs and finally one of breadcrumbs.
Get yourself and the kids on a production line of flour, egg, breadcrumb then either fry or oven bake.
Fishcakes, a mix of fish and mashed potato, formed in to patties and baked - again a 6 year old should be able to mix it, and can certainly help shape them (if you won't mind odd shapes).
Omelettes with various fillings, rolled omelette, soufflé omelette.
Scotch eggs. Don't try to get the slightly runny centre, that's for chefs to do, but hard boiled eggs, sausage meat - again 6 year old can help, then egg and breadcrumbs as above.
There is an Indian dish called egg nargis / nargis kebab it is very similar to a scotch egg but it has spiced lamb instead of the sausage meat.