The other day, as part of a cleaning out the cupboards, I found a bag of lentils and was inspired to make this soup. I believe we all use to make this regularly when we first began cooking. It is quick, easy and cheap, but forgotten for many years in mild California winters.
The French lentils from Le Puy are reputed to hold onto unto their shape with more determination than their beige German brethren. I've only used the beige, which cook up into a delicious soup. For my next lentil adventure, perhaps I'll buy the deluxe lentils and see if my discerning palate will get the difference.
It’s possible these distinctions are more important for salads. For soup? I do not know.
But on the assumption that it might, I'll suggest using the most elegant lentils you can find, with the caveat that it is delicious even with the most mundane of legumes.
I always improvise, but my current favorite base is from Deborah Madison--Vegetarian Cooking for Everyone--though when possible, i.e. if I happen to have chicken stock available I'll use that instead of all, or part, of the water.
Heat two tablespoons olive oil in a heavy bottomed soup pot. Add 2 cups finely chopped onions and sauté over medium heat until just beginning to brown (maybe ten minutes). While the onion is cooking, finely chop or crush 3 to 5 large garlic cloves. When the onion is cooked, add 3 tablespoons tomato paste, 1/2 cup finely diced celery, and 1/2 cup finely diced carrot, 2 bay leaves, and 1/2 cup chopped parsley. Cook for a few minutes. Add 1 pound of lentils (2 cups), 2 quarts water, or vegetable or chicken broth and ½ teaspoon salt. Bring to a boil. Lower heat and simmer partially covered until the lentils are tender and begin to disintegrate.
Add 2 tablespoons Dijon mustard, and 1 tablespoon sherry vinegar or red wine vinegar. Salt and pepper to taste. You can also serve it with slices of lemon or lime.
You can vary this with a final addition of spinach or sorrel. And, of course, you can use more or less of the other vegetables. If it's not tasty enough, be more enthusiastic with garlic, mustard or lemon. I used to add soy sauce--which you can play with as well.