In a large flameproof casserole or dutch oven heat the olive oil and add all of the sauce ingredients. Cook, uncovered for 20-25 minutes, stirring occasionally. If the sauce tastes too acidic add 1 teaspoon of sugar. PurÄe in the bowl of a food processor or blender. If the sauce is not quite thick enough after purÄeing, return it to the casserole and boil it hard until reduced and thickened. The sauce will keep for 1 week in the refrigerator.
