From "Bistro Cooking," by Patricia Wells (Workman).
Rinse lentils and discard any pebbles. Place lentils, onion, garlic and bay leaf in a medium saucepan and cover with cold water by 1". Cover and bring to a boil over medium heat. Reduce heat to low and simmer, covered, until lentils are tender, 25-35 minutes. Add liquid as needed; liquid should be absorbed when lentils are done.
Discard onion, garlic and bay leaf. Whisk vinegar, oil and salt together in a small bowl. Pour over warm lentils and toss. Before serving, season with pepper and additional salt, if necessary. Serve warm.
Makes 6-8 servings.