Preheat oven to 200°C. If you have them, place two pizza stones on separate shelves in the oven to preheat.
Alternatively preheat 2 oven trays. Get them really hot (this helps the bases crisp up on the bottom).
Heat olive oil in a medium fry-pan on medium heat. Sauté onion and garlic until soft, 3-4 minutes. Add tomato paste, crushed tomatoes, dried herbs and sugar. Simmer, uncovered, stirring occasionally, for 10-12 minutes until sauce is thick and the consistency of chutney. Season to taste with salt and pepper.
Place each pizza base on a sheet of baking paper so that you can lift the pizzas easily once the toppings are on. Spread half of the tomato sauce on each pizza base.
Arrange cherry tomatoes on each pizza. Sprinkle over mozzarella and parmesan.
Carefully transfer the pizzas with baking paper to hot pizza stone or oven tray. Cook for 12-15 minutes until pizza bases are crisp and cheese has melted. Scatter over fresh basil leaves.