1. Make the pastry dough. Begin with flour in a food processor, then add butter and pulse until mixture looks like fine breadcrumbs.
2. Add salt, and egg yolk, and enough cold water to form a stiff dough. Wrap and leave to rest in refrigerator for 30 minutes.
3. On a floured surface, roll out the dough until it is 15 3/4” x 7”.
4. Preheat an oven to 375° F.
5. Combine all the ingredients for the filling. Add salt and freshly ground black pepper, then mix well.
6. Slice the pastry dough in half lengthwise, making sure the two pieces don’t stick to the board. Brush the long edge of each pastry with egg wash.
7. Shape pieces of sausage meat and place onto each pastry, 1 inch from the left edge. Fold the other half of pastry over to cover filling.
8. Using a fork or pastry roller, press down to crimp the edges of the pastry.
9. Dust a knife blade with flour, then cut each pastry to form 1 1/2 inch rolls. Place all the rolls on a baking tray lined with parchment.
10. Brush each roll with egg wash and sprinkle black sesame seeds on top.
11. Bake for 22-24 minutes or until pastry is golden brown and sausage filling is cooked through.
12. Remove from oven and place on a cooling rack.

Serve with mustard and/or relish.