Smoky, Spicy Barbecue Sauce

Purée the onion vinegar, brown sugar, honey, and molasses in a food processor or blender. Put the tomato paste in a large nonreactive saucepan over medium-low heat. Pour the onion purée into the tomato paste and stir to blend. Bring to a simmer. Add the rest of the seasonings, and simmer the sauce for 30 minutes, stirring occasionally.

Remove the saucepan from the heat and ladle the sauce into a sieve placed over a bowl. Press the sauce through the sieve with the back of a spoon. Transfer to a lidded jar. Refrigerate, the sauce will keep indefinitely. Reheat before using.