I like to plan meals even though I'm retired. I make a lot of casseroles, double up and freeze it. I freeze gravy from the Sunday roast and use it in the week with chops, sausages from the local butcher or make a cottage pie. I make a lot of homemade stock for soup, though often forget to defrost it and then use Marigold veg stock powder.
We do a main shop once a week and pick up any extras in town. We do the 5.2 fast diet on Mondays and Thursdays mainly for health reasons. DH usually has herrings in a pot from Sainsburys with watercress, I have fish and salad or veg, something from the M&S Count on Me range, tinned tomatoes on toast. So it is 5 days to plan and shop for. Typically -
Sunday - a roast with plenty of veg
Tuesday - chicken kievs with cauliflower cheese or baked potato.
Wednesday - salmon, new pots and green beans.
Friday - pasta with either homemade tomato sauce or supermarket own, add mushrooms and chorizo or chopped sausage.
Sat - usually a curry in local pub.
Really quick option for us would be a mushroom omelette.
I've always have cheese, eggs, and mushrooms in the fridge, they can make a meal in minutes and transform most dishes. Dil doesn't eat meat and doesn't like mushrooms, so I aubergine as substitute in recipes for her - or dice the mushrooms so small she doesn't notice ?