1. Preheat your oven to 350°F (180°C) or 400°F (205°C) for a crisper pastry. Line a baking sheet with parchment paper.

2. Cook base ingredients like onions, garlic, celery, and bacon (if included) until softened and caramelized, then let them cool.

3. In a large mixing bowl, combine 1 kg of pork mince, 35g French onion soup mix, 1 tbsp tomato ketchup, 2 tbsp Worcestershire sauce, and any optional herbs or additions like thyme, sage, or breadcrumbs. Mix thoroughly to combine.

4. Lay puff pastry sheets on a flat surface. Brush a thin layer of egg wash over the surface of the pastry.

5. Spoon the prepared sausage filling in a log shape down the center of the pastry sheet.

6. Roll the pastry over the filling and seal the edges with egg wash. Crimp the edges lightly for a neat finish.

7. Cut the roll into desired lengths and brush the top of each piece with more egg wash for a golden shine.

8. Place the sausage rolls on the lined baking sheet, ensuring there is space between each one for even baking.

9. Bake in the preheated oven for 20-40 minutes, depending on the size of the rolls, until the pastry is golden brown and fully cooked.

10. Rotate the baking tray halfway through baking to ensure even cooking.

11. Remove the sausage rolls from the oven and allow them to cool slightly before serving.

12. Serve warm with a side of tomato relish, mustard, or dipping sauce of your choice.