I think it is all about arming yourself with an array of recipes that you can cook very quickly!
I always cook from scratch and rarely spend more than 15mins in the kitchen.
Tonight we had crab linguine - scrape the brown meat and white meat from a small crab into a bowl, stir in a glug of olive oil, a pinch of seasalt and a small chopped chilli. Mix together. Cook pasta, remove from heat and mix through the crab mixture.
Or pasta with pancetta. Chuck some pancetta into a sauce pan and heat over moderate gas util rendered down. Chop in some mushrooms and cook through. Cook pasta then stir in pancetta. You can do exactly the same with tinned tuna, although I add a whirl of natural yoghurt to moisten it a bit!
Omelette - whatever you like!
Fritatta - peel a load of onions and sweat in pan, peel and slice spuds - stick in pan on top of onions. Cook for an hour or so, then mix in a few beaten eggs. Cook until just set then serve.
Couscous with roasted veg. Peel mixed root veg, cut into chunks, slug over some olive oil and stick in oven for an hour or so. 5 mins before serving, pour boiling water over the couscous, chop some herbs through. Pie roasted veg on top and serve.
Soups usually only take a very short time to prepare - just chopping veg. Cook and serve with nice bread.
How about noodles - warm up some chicken stock - stick in some noodles and a finely chopped chilli (optional) then finely chop a carrot, some mushrooms and whatever else you have to hand. Stir through - leave for a few minutes to warm through then serve.
Or lamb shanks - prepare the night before in roasting tin - stick in the oven as soon as you get home. Peel and chop some potatoes, put in a foil parcel with rosemary and lemon juice - seal parcel and stick in oven with the lamb. Cook some french beans to serve.
Pork chops - peel an onion and slice and layer in a casserole dish. Put pork chops on top and put a small slug of white wine (or cider if you have it) in with them and some thyme. Stick in the oven for 40 mins. Serve with mashed pots and veg.
There are countless recipes you could do - make up a big batch at the weekend if you need to. I do this for chilli, curry, casseroles, macceroni and cheese, lasagne etc and then freeze - these are ready to warm through when you need them.