Preheat your oven to 375 degrees, line 2 baking sheets with parchment paper and set aside. Add the sage, parsley and garlic in a mini chopper (or finely chopped by hand) and pulse until finely chopped.

A large bowl, mix together the sausage, herb and garlic mixture, egg white and a small pinch of salt and pepper, set aside. Meanwhile, in a small bowl, whisk the egg yolk with a couple tablespoons of water to make the egg wash and set aside.
Lay out each piece of puff pastry on a lightly floured surface and roll it with a rolling pin to make it about 1/2” longer on the top and bottom, cut the puff pastry sheet in half lengthwise, take half of the sausage mixture, place it lengthwise in the center of the puff pastry forming it into a log as you go.

Brush the sides with some of the egg wash, place the other half of the puff pastry on top, seal the sides by using a fork and dipping it in flour and then cut out your slices of sausage rolls, place them on your prepared baking sheet and set aside.
Repeat with the remaining filling and pastry, then brush all the tops with the egg wash, sprinkle the tops with a touch of salt and pepper and bake the rolls for about half an hour or until golden brown all over.