Remove stems from mushroom. In a saucepan, cook 1 cup of heavy cream until reduced to half. Stir in chopped shallots, and cook for 1 minute. Remove from heat and stir in 1/2 cup coconut milk, cracker crumbs, shrimp, salt, black pepper, and dill. Stuff mushroom caps with shrimp mixture. Place in a shallow casserole dish.