If you like lentils this is a very good salad for a bento:
1 cup lentilles du Puy (French green lentils) picked over and rinsed
6 cups water
1 onion, chopped (not too fine; you will discard it)
3 bacon slices, chopped (this can be omitted for a vegetarian version)
1 garlic clove, halved
1/4 teaspoon dried thyme
1/2 cup fresh parsely leaves, chopped fine. Save the stems for cooking the lentils
2 carrots, diced fine (about 3/4 cup)
2 teaspoons white-wine vinegar
1 1/2 tablespoons Dijon mustard, or to taste (I do this to taste - that's a lot of Dijon!)
1/4 cup olive oil
In a heavy saucepan combine lentils and water. I place the onion, bacon, garlic, thyme, and parsely stems in cheesecloth bag, tie with a string, and simmer in the lentils, covered, 20 minutes. Drain the lentils and discard the cheesecloth.
In a seperate pot of fresh water, blanch the carrots and then drain. Mix the carrots with the lentils and chopped parsely (You can blanch the carrots in the lentil water, but they will take on color from the lentils, so I do them seprately becase it keeps them brighter and prettier in the salad.)
Transfer 2 tablespoons lentil-cooking liquid to a medium bowl and whisk in vinegar, mustard, and salt and pepper to taste. Add oil in a stream, whisking, and whisk dressing until emulsified.
Add the vinaigrette to the lentils, parsley and carrots, salt and pepper to taste. Can be made ahead; stores for about 2 days in the fridge. Can be served at room temperature.