Line a roasting tray with greaseproof paper, and preheat the oven to 200°C.
Cut the tomatoes and onions into quarters, place both in the roasting tray and pour half the olive oil, the salt and pepper, and herbs evenly across the top. Roast for 45mins.
Heat a large stockpot over medium heat the canned tomatoes and tomato paste. Carefully pour in the oven-roasted vegetables and their liquid. Mix thoroughly, simmer for 20mins.
Remove from heat, and allow to cool for 10mins, then using either a blender or stick blender, process until smooth - leave a few lumps if you want a more rustic style.
Serve with cheesy toast, or a grilled cheese sandwich, or topped with herby-croutons and a few shavings of parmesan cheese.