Line a strainer with 2 to 3 coffee filters or cheesecloth. Set over a bowl and place the yogurt in the strainer. Refrigerate for 2 hours to allow the whey (liquid) to drip from the yogurt. Discard the liquid and place the yogurt in a medium bowl. Add the tomatoes, garlic, olive oil, dill and milk. Combine well. In a blender, puree the mixture in batches, if necessary, until smooth. Pour into a bowl, add the vinegar and season to taste with salt and pepper. Chill for at least 1 hour. At serving time, ladle the soup into bowls and garnish with dill sprigs. Makes 6 servings (about 6 cups).
[per serving: 109 calories (51% from fat), 6 grams fat (3 grams sat. fat), 9 grams carbohydrate, 5 grams protein, 70 mg sodium, 15 mg cholesterol, 169 mg calcium, 1 grams fiber.]
Notes: Tested by Susan Selasky for the Detroit Free Press Test Kitchen July 29, 1998 Kitpath@earthlink.net 0. 30234315948.602