In my experience, I have always brought oil up on medium high heat and added curry leaves at this point. The leaves have to fry a bit to really develop their flavor in a dish - at least as I've found in South Asian restaurants and homes. You could definitely do a soup - frying up the curry leaves, lowering the temp and adding shallots and garlic, throwing in the squash for a bit, and then adding stock and a bay leaf and simmering until all cooked. Remove all leaves, puree, add cream. Would be lovely.

Try a butternut squash THORAN http://picasaweb.google.com/paulvj000/Thoran?authkey=Gv1sRgCMizif_3-_mx2wE#

I didn't mean to say that I have the best way. I mean my best way.

In my experience with curry leaves I have the best way to go about using fresh curry leaves is to infuse an oil then use the oil. To dry or even fry the leaves in oil and then grind them doesn't really give the flavor of infusef oil or butter. I'm going to let You decide what fat or oil to use look up Ghee (basically clarified butter). If I was just trying to use the flavor and not stay strickly to the indian culture I would use olive oil. Fill a pan with your leaves and add olive oil until they covered and bring the oil up to temp. Extraction occurs between 180-200F. Don't let it get any hotter than that and keep it there until you are happy with the flavor of the oil. Go by taste. usually the longer the better. Then suate your squash with the oil and maybe drizzle a little over after cooking. Understand that i'm not telling anything that has to do with cullure just a culinary technique of infusing oil.

I've made a curried squash soup with the addition of curried leaves. I didn't roast the squash with the leaves - I roasted and pureed it on it's own. Then I added the curry leaves to the soup while it simmered, and drained them out when I was done. It was delicious with yellow curry paste and coconut milk.