Heat oil in wok or deep skillet over medium-high heat. Add onion and bell pepper (if using raw shrimp, add now as well). Cook, stirring, until they soften. Add ginger and garlic and cook for another 30-45 seconds. Add curry paste and cook, stirring for 30-45 seconds. Add a few tablespoons of the cream from the top of the coconut milk and cook, stirring another 30 seconds. Add remainder of can of coconut milk, chicken broth and fish sauce. Add blanched and chopped asparagus and allow mixture to bubble away, stirring occasionally, for 3 minutes or so. Finally, add cooked shrimp and cook another few minutes to warm shrimp. Taste and add salt and pepper to taste. (You can also add additional curry paste, if you like).