Melt 1 tablespoon butter in pan over medium heat. Add shallots and garlic. Toss until almost golden. Add celery and toss for about 20 seconds. Add oysters and leeks and toss quickly. Add oyster juice and cream; toss. Add salt and pepper to taste and remaining 1 tablespoon of butter.
To Assemble and Serve:
Place stew in bowls and garnish with chopped parsley.