Heat 3 tablespoons of the oil in a large saucepan and add the onions, garlic, sugar and rosemary. Cover and fry gently for 10 minutes until the onions are soft but not brown, stirring occasionally. Add the tomatoes, stir and season well. Leave to cool slightly.

Roll out or press the dough, using a rolling pin or your hands, on a lightly floured work surface to fit a 30 x 18 cm/12 x 7 inch greased Swiss roll tin. Place in the tin and push up the edges slightly.

Brush the remaining oil over the dough and sprinkle with the cheese. Cover and leave to rise slightly in a warm place for about 10 minutes.

Spread the onion and tomato topping over the base. Drain the anchovies, reserving the oil. Split each anchovy in half lengthways and arrange on the pizza in a lattice pattern. Place olives in between the anchovies and drizzle over a little of the reserved oil. Season.

Bake in a preheated oven, 200°C/400°F/Gas Mark 6, for 18 - 20 minutes, or until the edges are crisp and golden. Cut into squares and serve immediately.