Preheat oven to 160°C.
In 2 (13 by 9-inch) pans place tomato halves cut side up. Sprinkle with oil, salt and pepper, onion, garlic, and herbs. Bake tomatoes for 2 hours.
Check the tomatoes after 1 hour and turn down the heat if they seem to be cooking too quickly. Then turn the oven to 205°C and bake another 30 minutes.
Remove from the oven and process tomatoes through a food mill on medium dye setting over a small saucepan. Discard skins. Add white wine, bring to a boil, reduce heat to low and cook for 5 minutes.