For pastry, combine flours, salt and butter in bowl and rub in butter to form breadcrumbs. Pour in egg and work to form dough. Cover and refrigerate for 1 hour. Roll and blind bake in 2 x 22cm tart forms, remove from oven and set aside.
For filling, preheat oven to 175°C. Spread mustard and olives over base of tarts. Combine the tomato, herbs, garlic, olive oil and seasoning. Layer this mixture with the cheeses.
Bake in oven for 30 minutes, remove and let stand for 10 minutes before cutting. Serves 4-6.
