By farmgirl susan's blog; makes 3 pints. If you double the recipe, add 10 minutes to the processing time.

2 lb. green tomatoes, cored and chopped
1 lb. white or yellow onions, chopped
3/4 lb. sweet red peppers, cored and chopped
1/2 lb. tart cooking apples, such as 'Granny Smith', cored and chopped
6 garlic cloves, finely chopped
1 cup 5% acidic organic raw apple cider vinegar (or less, see note below)*
1 Tablespoon kosher or sea salt
4 jalapeno peppers, cored, seeded if desired, and finely chopped
2 Tablespoons chopped cilantro
1 teaspoon ground cumin (optional)

Combine the tomatoes, onions, peppers, apples, garlic, vinegar, and salt in a large, nonreactive saucepan and bring to a boil. Reduce the heat and simmer, uncovered, stirring occasionally, until thickened, about an hour.

Stir in the jalapenos, cilantro, and cumin and simmer for 5 more minutes. Carefully purée the mixture using a stick immersion blender or in a traditional countertop blender, in batches if necessary, until still somewhat chunky.

If canning, return the puréed relish to a boil, then ladle the hot mixture into hot jars, leaving 1/4-inch head space. Process 15 minutes in a hot water bath. Store in a cool, dark place.

10 calories, 0g fat, 60mg sodium, 0g fiber, per Tablespoon

*October 2010 Update: Since I orignally posted this four years ago, a couple of people have told me that they followed the recipe but their green tomato relish ended up tasting too strongly of vinegar. The 1 cup of apple cider vinegar called for is to ensure that this is safe for water-bath canning (green tomatoes are acidic, but the other vegetables lower the overall acidity—1 cup is plenty), but if you're planning to store yours in the fridge (where it will keep for several weeks without processing) and are concerned it might be too much vinegar for your taste, you can safely decrease the amount of apple cider vinegar to 1/2 cup, or even less. If you want to give jars of green tomato relish as a gift without having to process them, just make sure the recipients put the jars directly into their refrigerator.