I often make my daughter olive pasta in one pot. I blend olives, celery, carrot, onion, garlic, and seasoning with a tin of tomatoes, fill the tin up with water, add a handful of pasta, pour it all in and put the lid on.
This makes a lovely nutritious pasta that she is guaranteed to like.
My husband will eat whatever I give him but I am always looking for new things to cook anyway so am glad to try recipes out. Today I've already done pate, donuts, three dishes that were used to make lunch and dinner plates, and I had curry and rice left over. So my husband's eaten all day while me and my daughter try new things. We made donuts for the first time.
Cooking and clearing up for three meals a day could be a full-time job on its own so meal prep is very useful.
I have a few staples -lasagne, cottage pie, bolognaise, curry and rice, and freezer tea- that fill the majority of most week's dinners.
Oftentimes there are leftovers in tubs of the above which can be used alone or combined to microwave a plate for a hungry spouse or child.
If you have time to make two different meals then great. But it's really not that big of an issue when it comes to a child, well not at mine's age, of 6, as waffles and beans/spaghetti hoops, the pasta I mentioned, or another quick tea can go in place of a freshly cooked meal. So I don't mind doing it.