Preheat the oven to 200 degrees C. Slice the tops off the tomatoes and roughly chop them. Peel the garlic and chop each clove in half. Place tomatoes and garlic in a roasting tray and drizzle with olive oil, salt and pepper. Bake for approximately 1 hour, or until the tomatoes start to blacken at the edges. Stir the tomatoes once, to loosen them up. Let cool slightly, then blitz tomatoes in a blender until smooth. Season to taste with salt, pepper and sugar.
This sauce may be used as a base for Italian cooking. Try it with fresh basil and parmesan cheese over pasta.