Preheat your oven to 180°C / 350-375°F / Gas Mark 4-5.
Remove frozen puff pastry sheets from the freezer and allow to thaw. Note 7
Use a sharp knife and chopping board to remove the casing from the sausages. (Discard).
Add pork mince, pork sausages, fennel, apple sauce, dried onion, salt and pepper to the food processor (dice blade). Blitz for 20 to 30 seconds to combine.
Working one sheet at a time, place thawed puff pastry sheet onto chopping board. Spoon pork sausage mixture into a zip lock bag, squeeze out excess air and cut a corner approximately 1.5 cm.
Pipe the sausage mixture onto the pastry in one log line. Roll the pastry over and use the beaten egg to seal the gap with a slight over hang.
Cut the long sausage roll into 4 even portions. Place these onto baking tray.
Use a pastry brush to coat the top of each sausage roll with egg. Sprinkle poppy seeds over each.
Place on the middle shelf in the oven and bake for 25 to 30 mins.
Serve with sauce.