Set the oven to 190°C/375°F/gas mark 5.
Mix the flour and salt in a large bowl.
Cut in the margarine with a knife until the mix is like breadcrumbs.
Add the cold water until the mix forms a dough.
Wrap the dough in baking parchment and place in the fridge for ½ hour.
Place all the chopped vegetables and herbs in a baking tray and toss in the olive oil.
Bake the vegetables for 25 minutes until tender and leave to cool.
Roll out the dough to 5 mm thickness and place in a tart dish.
Blind bake in the oven for 15 minutes.
Add the vegetables to the tart and bake for a further 30 minutes or until the crust is golden brown.