This is called 'La Pizza Rossa' in Apples For Jam, and the topping is a simple tomato sauce. I added a few toppings and sort of managed to keep the red theme - I added ham, cabanossi and a little cheese.
The base is exactly the same as the focaccia (see below), but instead of brushing with the oil/water/salt mixture after the second rise, a tomato topping is carefully spread over and the pizza is cooked in a hot oven for 20 mins or so until it has crisped up.
The edges were crispy and the middle was softer - if I had cooked it for longer the middle would probably have been more crispy, but I didn't want to burn the topping and I had hungry people waiting for their dinner!
Ingredients for topping:
4 tbsp olive oil
1 large garlic clove, peeled and squashed a bit
800 g tinned diced tomatoes
a few basil leaves, torn
1 tsp salt
plus I added a little sugar
Heat oil and garlic in a pan until you can smell the garlic, add the tomatoes, basil and salt and simmer rapidly for 15 mins or so until the sauce thickens.