Preheat your oven to 200°C (390°F).
Sauté the onion and garlic until soft.
In a large bowl, mix the sausage meat, sautéed onion and garlic, breadcrumbs, sage, thyme, salt, and pepper.
Roll out the puff pastry on a floured surface.
Cut the pastry into rectangles and place a line of filling along one edge.
Roll the pastry over the filling to enclose it and seal the edges.
Place the rolls on a baking tray lined with parchment paper.
Brush the tops with beaten egg.
Bake in the preheated oven for 25-30 minutes until golden.
Allow to cool slightly before serving.