I advise you to always cook the meat with some extra red sauce when you make tomato juice, good for pasta, and even puff pastry tarts if you have any leftovers.
Clean the meat from the bones and finely chop it.
Cut the puff pastry in the wanted shape and slice the very thin outlines to add them as a frame on top of the pastry so that the juices stay inside. Let the pastry stay for about one hour to completely melt (if you use frozen).
Put tomato sauce inside the pastry, add meat all over it and top with some grated cheese of your choice.