Preheat the oven to 400° F (200° C). Lightly butter a large baking sheet.

Heat the oil in a large heavy skillet over medium-low heat. Add the sausage and onion, and sauté them until the sausage browns and the onions are translucent, about 10 minutes.

Drain off the excess fat. Transfer the mixture to a large bowl, add the apples, cheese and stuffing and stir to combine well.

Beat one of the eggs, add it to the sausage mixture, and stir to combine.

On a lightly floured work surface, roll out each of the 2 pastry sheets to a 14 by 18" rectangle.

Spoon half of the sausage filling lengthwise down the centre of each rectangle, starting 3 inches from the top and ending 3 inches from the bottom.

Cut the pastry on either side of the sausage filling into diagonal strips about 1/2 inch wide. Fold the strips, alternately from each side over the filling to create a lattice or braid effect. Repeat the process with the second pastry sheet.

Beat the remaining egg with a few drops of water. Brush the egg wash over both pastries. Place on prepared baking sheet and bake for 30 minutes, or until the pastries are puffed and golden brown. Serve hot.