In a mixing bowl, add garlic, thyme, and lemon juice to the yogurt and mix well. Place mixture in cheesecloth, set over a colander, set over a bowl and place in refrigerator for 12 hours.
Discard liquid and place remaining yogurt in bowl. Add salt and pepper, to taste.
For an alternative, replace the lemon, garlic, and thyme with 1 1/2 teaspoons cumin and 2 tablespoons chopped parsley.