Can you boil spinach with less water? I usually boil spinach in quite a bit of water.  The spinach becomes tiny upon boiling leaving quite a bit of water with nutrients in it.

What is the least amount of water I could say boil 100g of spinach in? If I could boil the spinach and be left with just a small layer of green water to drink that would be great but most recipes seem to require boiling any sizeable amount of spinach in a sizeable amount of water.  What are the reasons for this?

Just to add, there are reason I was asking about boiling with more or less water.  I want the spinach to become very small which I notice happens with boiling but not to the same degree with steaming or other methods.  Also I want it to leach nutrients out and go into the little liquid. From Jefromis answers I can see that the spinach will cook, however I doubt it will go small, fibers will loosen, nutrients will leech to the same extent etc.  I'm bascially asking how much water is needed to for it to become very small, maximise fiber softening and nutrients leaching. I doubt this would occur in the in a little water or can we expect it to fully wilt with time?
You don't have to use any water at all.

Just heat it in a pot or pan, stir to keep it from only cooking on the bottom. It'll likely release enough water to end up essentially steaming itself, and yes, it'll be green water you can drink if you like.

You can also steam it if you like. If you use a very small amount of water to start, then the water released by the spinach will supplement it, and you'll end up with a bit more diluted water, but still probably green.

If you really want to boil it, you can use as little water as you like - a really small quantity will be enough that once it wilts it'll all be submerged. Of course, it's going to be substantially more diluted than if you didn't use water.

And yes, all of these will soften the spinach just as much and release plenty of the flavor and nutrients into the liquid, as long as you cook it long enough. Most people would likely regard that as overcooking, but you can cook as long as you want.