Begin by rolling out your pastry into a large rectangle (about 3mm in thickness). Allow it to rest while you make the sausage filling.
Crack the egg into a cup and roughly mix with a fork.
Preheat the oven to 200℃ fanbake.
In a medium sized bowl combine all the other ingredients, and mix well.
Spoon an even amount of sausage meat along the length of the pastry (about 3cm from the edge).
Roll the sausage roll up, and use the egg wash to seal the pastry. Cut along the length of the roll, and check the seal is closed by rolling the roll over. Divide into four or eight (depending if on the size you wish) using a sharp knife. Do not use a serrated knife, as it will leave quite a mess.
Egg wash and prick the pastry top with a fork.
Repeat.
Place on your oven sheet and cook for 45 minutes.
Any left over pastry can he used for a wee sweet pudding. Simply cut into little squares or triangles and bake for 5 minutes.