1.Preheat the oven to hot, 200°C. Lightly grease a 20cm spring-form pan.
2.In a frying pan, heat oil on high. Saute onion 3-4 minutes until tender. Stir thyme through.
3.Sift flour into a large bowl. Rub in butter using finger tips until mixture resembles breadcrumbs. Stir half of the cheese through.
4.Make a well in the centre of the flour mixture. Add milk all at once. Using a flat bladed knife stir through the milk to form a soft dough. Turn out onto a lightly floured surface and shape into a ball.
5.Press dough into the pan. Scatter onion over. In a large bowl combine soup, eggs and tuna. Carefully pour over dough. Sprinkle with combined chips and remaining cheese.
6.Bake 50-55 minutes until set. Rest for 10 minutes before serving. Sprinkle with parsley. Cut into wedges and serve with steamed green beans or salad and lemon wedges.
If you like, try adding some sauteed mushrooms with the onion.Note