Preheat Oven:
Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

Prepare the Filling:
Heat olive oil in a skillet over medium heat. Add diced onion and cook until soft and translucent, about 5 minutes. Stir in the garlic and cook for another minute.
Remove from heat and let cool slightly.

Mix the Sausage Filling:
In a bowl, combine the sausage meat, cooked onion mixture, sage, thyme, salt, and pepper. Mix until evenly blended.

Roll Out the Pastry:
On a lightly floured surface, roll out the puff pastry into a rectangle (about 10×12 inches).

Assemble:
Spoon the sausage filling along one long edge of the pastry, forming a log. Roll the pastry tightly over the filling and seal the edge. Place seam side down on the baking sheet.

Slice and Brush:
Cut into 1½-inch (4 cm) pieces and place evenly on the baking sheet. Brush each with beaten egg for a glossy finish.

Bake:
Bake for 20–25 minutes, or until the pastry is golden and the sausage is fully cooked.

Serve:
Let cool slightly before serving. Enjoy warm or at room temperature.