In a mixing bowl combine crab meat, green onion, Tabasco sauce and mayonnaise and blend together.
Set out frozen puff pastry about 20 to 30 minutes before ready to use.
On a working surface place the brie and cut a ring about an inch from the side and left out the center ring and remove some of the brie and spoon in the crab meat mixture and place the center pieces back in place.
Roll out pastry to 1/8" thickness. Cut off a 4" strip and set aside to use as decoration.
Place Brie in center of puff pastry and bring up edges and crimp edges together around Brie, sealing completely. Turn Brie - crimped dough side down on a backing sheet. With remaining 4" of dough left cut out leaf design or anything you may want to use as a decoration. Place on top of dough covered Brie. Refrigerate until ready to bake. This can be kept overnight for your convenience. Just cover with plastic wrap.
When ready to bake - remove plastic wrap. Mix egg yolk with 1 teaspoon water and brush entire dough covered Brie.
Preheat oven to 400°. Bake for 15-20 minutes. Remove from oven and let set 20-25 minutes before serving.