On a floured surface roll out the puff pastry block into a ⅛" thick rectangle. Divide into 2 cutting in half lengthwise. You will have to long strips.
Score the sausages with a sharp knife and remove the casing. Arrange 3 sausages on each strip closer to one side, spread the sausage meat if necessary to fit the length of the pastry.
Brush one side of the pastry with beaten egg and fold it over to cover the sausage. Seal the edges with a fork and brush with an egg wash all over. Slash with a sharp knife, so steam can escape while baking. Sprinkle with sesame seeds or poppy seeds.
Transfer 2 long sausage rolls to a baking sheet, then cut each into 3 smaller ones. Bake for 25 minutes.