it may be of interest to you a system i worked out a few years ago:
it was for my diploma in outdoor activities, which involved 8 months on and off hiking/camping climbing etc.
after a couple of trials i came up with a recyclable, washing up free ration!
i got the idea from a friend of mine who as a student hated washing up so covered his plates in cling film
long time ago!
basically everything i used only required hot water.
pasta meals
custard and applepie
porridge
cake
fruit tea
first remove packaging and place in seperate (recyclable) freezer bags, you have the option of the pot cooking or in the bag which isn't as nice but when on a mountainside very handy!
if you can cvope with eating out of plastic bags the only thing you will have to wash is your spoon! many times i rested on my laurels whilst others had to try to wash pots or messtins in a cold stream!
P.s. fruit tea does not require milk Therefore you don't need to bring milk!
once eaten the used bags get stuffed in a "rubbish bag" till you get home you can then recycle or wash out for another time.