French green lentils have an intense, earthy flavor that is the star of this dish.

In a large saucepan, heat 2 teaspoons of olive oil over medium heat. Add the onion, celery and carrot and saute until the vegetables are softened, about 5 minutes. Add the garlic, mustard seed and fennel seed, and saute until the spices are fragrant, about 1 minute.

Add the stock, water, lentils, thyme and bay leaf. Raise the heat to medium high and bring to a boil. Reduce the heat to low, cover partially and simmer until the lentils are tender but still firm, 25 to 30 minutes. Drain the lentils, reserving the cooking liquid. Transfer the lentils to a large bowl and discard the bay leaf.

In a small bowl, combine the vinegar, mustard and 1/4 cup of the reserved cooking liquid. (Discard any remaining liquid or reserve for another use.) Whisk in the remaining olive oil.

Add the vinaigrette, parsley and pepper to the lentils and toss gently to mix and coat evenly. Serve warm.

• 4 tablespoons olive oil, divided
• 1/2 yellow onion, finely chopped
• 4-inch-piece celery stalk, finely chopped
• 4-inch-piece carrot, peeled and finely chopped
• 3 cloves garlic, minced
• 1 teaspoon mustard seed
• 1 teaspoon fennel seed
• 2 cups vegetable stock, chicken stock or broth
• 1/2 cup water
• 1 cup French green lentils, picked over, rinsed, then drained
• 1 tablespoon chopped fresh thyme or 1 teaspoon dried thyme
• 1 bay leaf
• 1 tablespoon sherry vinegar or red wine vinegar
• 1 tablespoon Dijon mustard
• 2 tablespoons fresh flat-leaf (Italian) parsley, cut into strips
• 1/4 teaspoon freshly ground black pepper