2 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 millimetre 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.