Base: Mix all ingredients into a soft dough in a food processor or by hand. Press into base and sides of a greased 24 cm quiche pan.
Filling: Heat oil in heavy-based pan. Saute leeks and garlic for a few minutes until soft. Remove from heat and set aside. Add tomatoes and spoon into base.
Whisk cheese sauce, milk, eggs, herbs, sugar and seasoning together and pour over leeks and tomatoes in base.
Sprinkle over Parmesan cheese and bake at 180°C for 30–40 minutes or until set. Serve warm and cold with a salad.