Heat olive oil in frypan over medium heat. Add onion and cook until soft and golden but not brown. This will take approx. 30-40 minutes stirring frequently and watching carefully so that onions do not brown.
ADD extra oil if necessary. Meanwhile roll out pastry very thinly on floured surface, then place on a greased 15x9 inch (2L) pan. Generously prick with fork and refrigerate. When onions are cooked slightly.
PREHEAT oven to 450° F.(220C) spread cooled onions over pastry. Slice tomatoes and arrange over pastry. Slice tomatoes and arrange over onions. Top with anchovies - (if you like them) and olives. Season with fresh ground pepper - (to taste)
BAKE 20 minutes. Cut into squares and serve warm or at room temperature. Can be served with drinks or as a first course.Servings: 6