Preheat the oven to 1800C. Roll out the pastry thinly.

Press the Puff Pastry into the tin using your fingertips, pushing it into the edges. Leave an overhang of pastry around the sides of the tin. Use a fork to prick the base of the pastry.

Line the tart tin with baking parchment and fill with ceramic baking beans or dried pulses.

Bake for about 15 minutes or until the pastry is firm, then remove the beans and cook for about 5 minutes more, until golden brown and biscuity. Trim any excess pastry before filling.

Whilst still warm place 1 1/² tablespoons of onion marmalade on the base and spread.

Cut the brie into pieces and place on top of the jam with the pine nuts.

Dilute 1 tablespoon of marmalade with 1 tablespoon of water and drizzle over the tart. Sprinkle with some thyme, and return to the hot oven. Grill until the cheese starts to melt.

Remove from the oven. Add some extra thyme on top and serve.