For high volume food service establishments, scale up the ingredients to meet your needs.
Make a large batch, heating the gravy and adding the other ingredients, holding it hot for service time. Also, prebake quantities of the puff pastry toppers on sheet pans. This way, when an order comes in during an ala carte service, or plating a banquet, just ladle the hot filling into the service vessel and top with pastry. Serve and watch your guests rave!