• Preheat the oven to 190℃/374℉ and line a baking tray with baking paper or a silicon mat.

Let's make the filling

• To a large bowl, add the chicken mince, salt, chopped parsley, chopped chives, mayonnaise, mustard powder and black pepper.
  500 gram chicken mince, ¾ teaspoon salt, 1 tablespoon chopped parsley, 1 tablespoon chopped chives, 2 tablespoons mayonnaise, ½ teaspoon mustard powder, few grinds black pepper
• Use a fork to combine everything. Set aside.

Prepare the puff pastry

• To prepare the puff pastry sheet, unroll it while keeping it on top of the original paper it was rolled up in. No need for a floured surface for this step.
  1 pack ready-rolled puff pastry 
• The sheet should be around 37cmx25cm/14.5''x10'' in size. If it's smaller than that, roll it slightly bigger with a rolling pin. It does not have to be precise.
• With a sharp knife, slice the pastry sheet in half lengthwise so you end up with two long strips.

Assemble the sausage rolls

• Divide the chicken mixture into two equal portions and spoon each half onto the two halves of pastry.
• Shape each portion into a long, sausage-like shape, running along the length and middle of each strip of pastry.
• Make sure to distribute the filling evenly from end to end, for an equal spread.
• Whisk the egg briefly in a small bowl.
  1 egg
• Take a pastry brush and use it to brush the beaten egg along one long side of the pastry, creating an egg-washed strip about 1.5cm wide.

  Repeat the process for the second pastry strip.
• Take the side of the pastry that doesn't have the egg wash and carefully fold it over the sausage mixture.
• Bring the egg-washed side of the pastry strip over to overlap the other side.

  The egg wash will act as a glue to hold the pastry together where the two sides overlap.
• Using your fingers, press along the seam to ensure it holds well and that there are no gaps.

  Don't hesitate to gently stretch the pastry where needed, as it is quite flexible.
• Repeat the same process for the other strip of puff pastry.

  Don't worry if it doesn't look perfect at this stage, as it will become smooth and beautiful once baked.
• Roll each tube over, seam side down. Use clean hands to shape the rolls, smoothing out any lumps or bumps.

  Gently press down on the tops to create a slightly less rounded shape.
• Slice each roll into 8 pieces, ending up with 16 sausage rolls altogether.

  You can make these bigger if you prefer larger sausage rolls.
• Using the tip of a knife, make two small slits on the top of each roll. These slits will allow steam to escape while the rolls are baking.
• Transfer the sausage rolls onto the baking sheet lined with parchment paper or a silicone mat.
• Brush the sides and top of the pastry generously with the rest of the egg wash to ensure a crispy, golden top.
• Optional- Sprinkle the top of the rolls with sesame seeds and/or chopped or dried parsley.
  optional - sesame seeds for decoration
• Bake in the preheated oven for 30-35 minutes, or until golden brown and well risen.

  Larger rolls will take a little longer, so look out for the above visual clues.