OMG I had never thought of that. You could like, use things like tomato puree, onions and herbs to give it a bit of flavour too couldn't you. My tip is, once you have done this, tell any other members of household that "this is meant to be four portions" just to make sure day 2 does not turn into "seconds"
MiceElf so glad you mentioned the labels as it is very annoying when you defrost something you think is a main meal and you look and find an "apple pie" it defeats the object somewhat, then you have to run to the nearest takeaway
And, if you want to make day two a little different, you add a 'little extra' to the dish after you have defrosted it. Ideas might include a little tomato cut into a water lily shape or a few snipped chives (they're easy to grow on your windowsill) or even, with a fish dish, a lemon slice.
And to be really thrifty use the left over portion / spoon of soup as a sauce for the meal you made by blanching the outer leaves of leeks (which profligate people discard) and stuffing with the ends of pieces of cheese which you have grated, mixed with a little mustard (there are some economical brands) a few toasted breadcrumbs and seasoning. You could serve this with freshly baked bread, or, if you have a few crusts left over, spread them with a little garlic butter and bake in the oven ( at the same time as the main dish obviously so you don't waste fuel).
Here's one I stumbled across that has stood me in good stead. Ask visitors if they are veggies BEFORE they arrive for Sunday lunch, then you can provide a non-meat snack whilst the rest have their roast beef.