Place one snail in each hole of escargot dish. Generously cover with
butter mixture. Place 1 sheet of puff pastry dough over each escargot
dish. Trim dough and seal around edge of dish. Beat egg with water and
use to brush dough. Chill until ready to bake, at least 20 minutes.
Preheat oven to 375 degrees. Bake until pastry rises and is golden, about
20 to 30 minutes. Remaining butter mixture can be refrigerated as long as
2 weeks and used when garlic butter is needed.