In a heavy-bottom pan on medium heat, melt the butter. Add onions and cook for 5 minutes, or until soft. Add sliced mushrooms, salt, pepper, dill, and paprika and cook for 15 minutes. Add the flour and stir for 5 minutes. Add water and bring to a boil. Once boiling, reduce heat to a simmer and cook for 15 minutes. Add the half-and-half and cook for 5 minutes. Add the sour cream and parsley and serve in warmed bowls. Freeze the leftovers or bring some to your neighbors.