For pastry: Sift together 2 cups flour and pinch salt in a medium bowl. Make well in center and add butter. Using fingertips, mix in water to form a smooth dough. Knead lightly and refrigerate for 1/2 hour. Preheat oven to 400 degrees F. Roll out pastry to a 10-inch circle. Set aside. Place some flour in a bag and add oysters. Shake to coat. Brush bottom of pastry with egg white, reserving some for crimping edges. Place oysters on 1 half of pastry circle. Season with salt and pepper. Top oysters with bacon, sprinkle with lemon juice and cover with tomatoes. Season with pepper and parsley. Brush edges of pastry with remaining egg white and fold over to enclose oysters, crimping edges together. Brush surface with whole beaten egg. Place pastry on a greased baking sheet. Cut steam vents in center and bake for 35 minutes.