One of the things that appeals to me about permaculture is the idea of stacking functions - that is, trying to find multiple yields from one element. Probably the quickest place I've found a use for this is in the kitchen. I try and use as many elements of my food as I can, and plan meals that make use of ingredients from previous meals. So, making mashed potatoes for dinner and potato pancakes the next day, having fish for dinner and then making a stock from the bones, heads and skin for the next night's meal, etc etc.
Making stock is incredibly easy, if you don't already do this. Any bones or leftover bits of meat get used. I save all my edible peels in the fridge - carrot, onion, leek ends, any trimmed off bits of veggie that can be eaten can be made into stock. I put them in a cast-iron casserole with plenty of water and cook 'em down. the stock gets drained and frozen, if it's vegetable. If there's meat in the stock, i put it in the fridge to chill. Once the fat sets, I skim it off the top, reserve that for cooking, and freeze the stock. When draining I usually pour through a metal sieve, discarding the last tablespoons of stock (along with whatever small bits might have settled) at the end. I used to pour that through the sieve too, but occasionally bits would make it through, and I used up more water cleaning the particles out of the sieve than it would have taken to make another batch of stock.
Cooking the stock - this depends on the weather. In summer I'm more likely to do this on the stove; boil faster with more heat for a shorter amount of time. In colder weather, I bake the stock. The slow heat over a longer period of time helps warm up the house. Since the stove is gas but the oven is electric, i"m not sure which is more energy efficient - something to research, I suppose.
I have a drawer in the freezer that is full of stock, and I make an effort to rotate through the older containers before using the newer ones. I was freezing stock in ice cube trays for a while, but found that a bit cumbersome. Now I just fill tupperware-like containers and freeze them in blocks. if I need less stock than is in a container, i'll just pull out a block, put it in a pan and melt off the amount I need, then return the rest of the block to the fridge. Planning in advance helps here too - you can just leave the block in a covered pan all day, or melt it on the stove if you're in more of a hurry.
Additionally: I bake my own bread, and when slicing a loaf, i sweep the crumbs into a little plastic container. When I'm heating up a pan on the stove, before I add the oil, i dump the container into the pan and toast the crumbs. by the time they're golden, the pan has warmed up. crumbs go back in the container - which i leave open till they cool - and I use the pan for whatever else. I made fish and chips last night, and the crumbs were the perfect thing for batter. I also use 'em to thicken stews, or for bread pudding - although it's rare a loaf lasts long enough to be stale for bread pudding.