In a large pot, heat the oil over medium heat. Add the chopped vegetables and cook, stirring, until softened but not colored, 6 to 8 minutes. Add the Essence, bay leaves and thyme, and stir. Add the garlic and cook, stirring, for 30 seconds. Sprinkle in the flour and stir to coat evenly. Cook, stirring with a heavy wooden spoon, until thick and a light roux forms, 6 to 8 minutes. Add the stock, stirring until well blended. Bring to a boil. Reduce the heat and simmer uncovered, stirring occasionally, for 30 minutes.
Add the heavy cream, salt, cayenne pepper and crabmeat and simmer for 5 minutes.
Place King crab legs in a steamer to heat up. Remove the soup from the heat and adjust the seasoning, to taste. To serve, ladle the soup in deep rimmed bowls.
Garnish each serving with 1 King crab leg, green onions, and chopped parsley. Serve hot.
Yield: about 1 1/2 quarts, 6 servings