Drain water off spinach and press out as much as you can with paper towels. Combine spinach, artichoke hearts, Parmesan cheese, sour cream, onion, garlic and salt and pepper and mix well.
Spread out the individual sheets of pastry and place an equal measure of the spinach mixture on each sheet. Spread mixture evenly on pastry. Roll up each sheet in a jellyroll shape. Wrap in plastic wrap and chill for several hours.
Remove plastic wrap and cut rolls into one half inch pieces.
Place on a non-stick-baking sheet and bake at 400 degrees F for about 20 minutes.