French Lentils with Smoked Sausage

From the garden

• 1½ cups French green or brown lentils, rinsed and picked over · a shape-holding class; red lentils dissolve and turn this into soup
• 2 medium carrots, diced small
• 1 medium yellow onion, finely chopped
• 3 cloves garlic, minced
• 4 sprigs fresh thyme
• ¼ cup fresh parsley, chopped

From the pantry

• 12 oz smoked sausage (kielbasa or saucisse de Montbeliard), cut into thick coins
• 2 stalks celery, diced small
• 1 bay leaf
• 4 cups chicken stock · or water; top up if the pot runs dry
• 2 tbsp olive oil
• 1 tbsp Dijon mustard · stirred in at the end
• 1 tbsp red wine vinegar · plus a few drops more to finish
• 4 slices crusty bread (optional) · for the broth at the bottom of the bowl
• salt · to taste
• black pepper

1. Rinse the lentils and pick them over on a pale plate for grit and small stones, which turn up more often in a home threshing than in a bought bag. Skip any soaking, since lentils need none.
2. Warm the olive oil in a heavy pot over medium heat and brown the sausage coins on both sides, 4 to 5 minutes. Lift them onto a plate and leave the rendered fat in the pot.
3. Cook the onion, carrot, and celery in that fat until soft and just taking color, about 8 minutes, then stir in the garlic for a minute more.
4. Add the lentils, thyme, bay leaf, and stock. Bring to a boil, then simmer partly covered 25 to 35 minutes, until the lentils are tender all the way through with no chalk at the center. Cooking them fully tender is what makes them digestible, so keep going if they still bite hard.
5. Return the sausage and any juices for the last 10 minutes of that simmer, then take the pot off the heat and stir in the mustard and vinegar. Acid slows softening, which is exactly why both wait until now.
6. Fish out the bay leaf and the bare thyme stems, season with salt and pepper, and fold through the parsley. Serve in shallow bowls with bread, adding a few more drops of vinegar if the pot tastes flat.