Step 1

Make the dressing: Combine the shallot, vinegar, lemon juice, Dijon, 1 1/4 teaspoons salt and black pepper to taste in a bowl. Let sit 5 minutes to dissolve the salt, then whisk in the olive oil until blended.

Step 2

Put the lentils, bay leaf and thyme sprigs in a 4-6 quart pot along with 2 teaspoons salt and 6 cups water. Bring to a boil, then reduce heat to a simmer and cook 15 minutes.

Step 3

Add the carrots, celery and onion to the lentils and continue cooking 5 - 10 minutes, until the lentils are tender. They will have absorbed most, but not all of the liquid.

Step 4

Drain the lentils and transfer back to the pot or to a serving bowl. Pluck out the bay leaf and thyme sprigs and discard. Pour the dressing over and stir to coat. Add the parsley and spinach and stir through.

Step 5

Sprinkle the cheese and walnuts over the salad and serve warm or at room temperature.