In a medium bowl, mix together ground pork sausage, onion, celery, parsley and pepper.
Roll one pastry sheet into an 8x12 inch rectangle. Spread with 1/2 the sausage mixture. Beginning with one of the shorter sides, roll pastry. Moisten with water. Seal the edges with a moist fork. Slice the roll into approximately 1 inch pieces. Repeat with second pastry sheet and remaining sausage mixture.
Flatten the roll pieces onto a large baking sheet. Bake approximately 20 minutes, flipping after 10 minutes, until sausage is evenly browned and pastry is golden brown. Drain on paper towels and serve warm.