Prepared in 20 minutes or less.
Mince together the parsley, green onions, celery leaves, tarragon and chervil as finely as you possibly can. Take as much time as you need. Mince them more finely than anything you’ve ever minced in your life.
Mix this together with the bread crumbs and the softened butter into a mortar and mix the whole thing together into a smooth paste, but do leave a little texture to it. (You can do this in a blender or food processor, but you’ll leave a lot of it behind, stuck to the inside) Season to taste with salt and pepper, Tabasco or Crystal and, if you like, the Herbsaint.
Lower the top rack to the middle of the oven. Spread the rock salt (preferable) or kosher salt over a large baking sheet; this will keep the oysters level under the broiler, so that they won’t tip over. Moisten the salt very slightly. Plant the shells in the salt, making sure they’re level.
Place one oyster in each shell, plus a little bit of oyster liquor. Spoon an equal amount of the prepared herb/butter mixture over each oyster.
Place the baking sheet on the middle rack and broil until the edges of the oysters have curled and the herb butter is bubbling, about five minutes. Watch carefully to make sure you don’t overdo it. Serve immediately.