Preheat your oven to 200°C (400°F).
Sauté the onion and garlic in a pan until soft.
In a large bowl, combine the sausage meat, sautéed onion, garlic, thyme, sage, salt, and pepper.
Roll out the puff pastry on a floured surface and cut into rectangles.
Place a spoonful of the sausage mixture onto one side of the pastry rectangle.
Roll the pastry over the filling and seal the edges with beaten egg.
Place the rolls on a baking tray lined with parchment paper.
Brush the tops with more beaten egg and make slits for steam.
Bake for 25-30 minutes or until golden brown.
Let cool slightly before serving.