Heat the oven to 200°C and line a baking tray with parchment paper.
Unroll the puff pastry and cut it into thin strips about 1 cm wide.
Brush a light layer of Dijon mustard over each sausage.
Wrap the pastry strips around the sausages in overlapping layers, leaving small gaps near the top for eyes.
Place the wrapped sausages on the tray and brush them with the beaten egg.
Bake for 20 to 25 minutes until the pastry is golden and crisp.
Remove from the oven and let them cool for a few minutes. Use the remaining Dijon mustard to dot two small eyes on each roll.