Preheat the oven to Gas Mark 6/200°C/fan oven 180°C.

Mix together the courgettes, red onion, mushrooms, garlic, rosemary, olive oil, balsamic vinegar and seasoning. Arrange them on a non stick baking sheet lined with non stick baking parchment and roast for 15 minutes.

Remove the vegetables from the oven. Arrange all the vegetables, including the tomatoes, on the base of a 20 cm (8 inch) non stick frying pan or cake tin.

Roll out the pastry on a lightly floured surface to make a 23 cm (9 inch) circle. Lay the pastry over the vegetables, tucking in the edges all the way round. Bake the tart in the oven for 20 minutes until the pastry is well risen and golden.

Carefully run a round bladed knife around the edge of the pan or tin. Put a large plate over the top and turn the pan or tin upside down, so the tart drops on to the plate. Cut the tart into quarters to serve.