In a medium oven proof frying pan, heat olive oil over medium heat. Add cherry tomatoes, balsamic vinegar and sugar. Cook, with minimum stirring, for 4 minutes. Season with salt and chopped fresh herbs mixture. Lay the pastry over the top pushing edges onto the pan.
Bake in the oven until pastry is lightly browned. Remove, allow to sit for 4 minutes, and invert over a platter. Cut in slices and serve.