Yes, perfectly safe to eat Butternut squash at any stage of development. The flavor might not be the best, but then again it might be quite good.

I think I have also read that the squash tastes better after it has been cured a while. Not sure if this applies to one that's not fully ripened, but it might be worth a shot. On the other side of that equation is the fact that early picks don;t keep as well. So, I'd give it some time to sit, but not too much.

Dontcha hate all this ambiguous advice? :-)

Thanks so much for the helpful advice. I will let them (there are 2)sit a few more days and then on to soup right from the earth in my backyard. I am so excited. I see 6 more developing but I will use a pair of younger eyes to look before I pick them.

It really does depend on whether you plan to store them. For storage, leave them on the vine as long as possible. For immediate consumption, pick them whenever you want to eat squach.

It's better to pick and use the younger fruits than try to store them while still immature.

They're definitely sweeter the longer you leave them on the vine itself. I've picked a few at the stage you described and they were still very tasty just not as sweet as they could've been. However, they'll work great still in soup!