Preheat oven to 180C fan-forced and line two oven trays with baking paper.
Mix the sausage mince, carrot, apple, celery and onion in a large bowl with the tomato sauce/paste and the herbs.
Lay the pastry all out on the bench and cut each piece in half down the middle to make two rectangles.
Lay a sausage shape of mince mixture down the middle of each pastry half lengthways.
Once all the mince has been used up, fold one side of the pastry over the filling then fold the other side over the first and turn it seam-side down.
Carefully cut each roll into 6 pieces and place on the oven trays leaving 1-2cm between each one.
Combine the egg and milk in a small bowl and brush on top of the rolls.
Sprinkle with sesame seeds if desired.
Cook for 40-45 minutes or until golden and cooked through.