In a bowl, mix the crushed tomatoes, oregano, sugar and a generous pinch of sea salt.
Place the pita bread on a lined baking tray and brush edges lightly with olive oil.
Divide tomato mixture amongst the 4 pita breads and spread evenly with the back of a spoon. Add the torn mozzarella, basil leaves and another drizzle of olive oil.
Cook for 10 - 15 minutes or until the cheese has melted slightly and the edges are browned and crisp.