Combine the roasted meat of one butternut (or similar) squash with 2 cups chicken broth and puree in a blender. (May have extra pureed squash which can be frozen for another time).
To make caramelized onions:
Slice one large onion in to rings. Place sliced onions, 3 tablespoons of butter, and 3 tablespoons of brown sugar, packed, into a skillet and cook until onions are brown and soft and all of the liquid has dissipated. Set aside.
In a large pot, combine pureed squash and remaining chicken broth. Add all remaining ingredients (Except for the orzo, butter and Parmesan cheese) and bring to boiling.
Add the orzo and simmer until orzo is soft and mixture thick for serving.
Stir in butter and cheese.
Serve immediately. Freezes well.