Fill the bottom of a shallow baking pan with ice cream salt and run pan into oven. When salt has become very, very hot, remove the pan and arrange on the hot salt clean, open half-shells of Oysters. Place one Oyster in each half-shell. While the salt is heating fry bacon crisply, chop into small pieces and mix with chopped up onion tops, parsley, chervil, celery leaves, seasoning and butter. Place a spoonful of this mixture on top of each Oyster. Then add a spoonful of cooked spinach. Over this sprinkle bread crumbs which have been browned and buttered. Place Oysters in oven and let remain until they begin to curl up on the edges — about five minutes. Remove and serve.