Saute green onion, garlic, mushrooms and ginger with the olive oil in a large saucepan over moderate heat until just beginning to color. Stir in curry paste and continue to cook and stir for 2 minutes more. Add stock, wine and 1 1/2 cups of the coconut milk and reduce over high heat by half (approximately 5 to 7 minutes minutes). Add cream and reduce to a light sauce consistency. Strain carefully pressing down on the solids and return to the saucepan. Stir in lime zest, juice, remaining 2 tablespoons of coconut milk and season to taste with salt and pepper. Keep warm.
Note: Shellfish stock can be easily made by simmering raw shrimp shells (which hopefully you've saved in the freezer after you've peeled raw shrimp) with chicken stock and a splash or white wine for 5 to10 minutes. Alternately you can add a bit of shrimp paste (available in jars in Asian markets) or dried shrimp (available in Hispanic or Asian markets) to flavor the basic chicken stock. Don't ever use bottled clam juice!