I've learnt to do little prep jobs throughout the day, so that at teatime (melt down hour often in our house), tea is either a ten min job, or pop in oven and put pan on with little effort.
3 dcs here, youngest 15mo. I always have jkt pot on menu each week, beans & cheese, or tuna and sweetcorn, with salad. Often I'll pop the potatoes in the oven with roast chicken on sun, so just microwave 5mins mon quick tea, but still good skins! Then chicken leftovers tues, usually with a rice or noodle dish to bulk out with stir fry veg.
I do make a huge pot of bolognese or veg pasta sauce once a week or so and freeze portions, but tend to start it off in the morning, so all the chopping and fiddly bits get done when ds2 is happily pottering.
I find meals with chicken breasts, salmon etc good as foil parcels, again pop the meat or fish in foil parcels early in the day and put the baking tray in the fridge (this way I can put flavours the dcs refuse on ours and just mild flavours / lemon on theirs). Then 20 - 30 mins in oven, and veg / carbs choice on to boil or stir fry at the last minute during that time.
If we're having a stir fry rice dish, I'll often fry off an onion early in the day and let it soften over a low heat, sometimes with some spices, so I can add that to the rice later when it's cooked. I might add veg, eg pepper, courgette, mushroom, then pop it in fridge to add later.
Have given up on making my own fish cakes (I feel your pain) but do tend to have one meal a week of some form of breaded fish / Fishfingers with oven chips / waffles / new pots / wedges with veg.
Mash is another one I tend to make and mash in morning, then reheat at teatime, so eg sausage and mash sort pots and prep any veg ready in morning, then pop sausages in oven at teatime and just reheat mash whilst veg boiling.