Spread the sugar in the prepared tin. Caramelize for approx. 7 mins. in the centre of an oven preheated to 220 °C until the sugar turns light brown, remove. Spread the butter, balsamic and thyme over the caramel. Place the shallots on top so that they overlap slightly.
Approx. 20 mins. in the centre of an oven preheated to 220°C, remove.
Prick the dough firmly with a fork and place loosely over the shallots. Make a rim between the shallots and the edge of the tin.
Bake for approx. 15 mins. Remove from the oven, leave to stand for approx. 2 mins., tip out carefully onto a cake plate, remove the baking paper, season. Serve the tarte tatin warm or cold.