Combine softened butter, parsley, green onion, garlic, salt, pepper, and Pernod, if desired, in a large mixing bowl; blend well.
Combine 1/2 cup breadcrumbs and wine; add to butter mixture, mixing well.
Fill shells half full with seasoned butter. Place snails in shells. Pack remainder of each shell with seasoned butter. Sprinkle with breadcrumbs.
Place shells in snail pans, or pour rock salt into a 13- x 9- x 2-inch baking dish to cover bottom (salt helps shells sit upright); arrange shells, open end up, on salt. Bake at 375° for 10 to 12 minutes. Garnish with parsley sprigs.