Heat the oven to 200°C /fan 180°C /gas mark 6
Heat a little oil and gently cook the onions until translucent
Mix the sausage meat with the onion and parsley and season
Unroll the pastry and lay it on a baking sheet. Brush the middle, lengthways, with the Strong English
Mustard. Form the sausage mix into a big sausage and lay on top
Make diagonal cuts, 1-2cm apart, in the pasty either side of the sausage and then bring the strips up
and over alternately to form a plait
Brush with the egg and scatter the sesame seeds on top. Bake for 25-30 mins until puffed and golden