Just the thought of lentil soup, a classic favorite, can arouse heady associations of warm, savory satisfaction.

This version overflows with good things to round out its rich flavor spectrum: leeks and kale, tomatoes and sweet potato, thyme and basil, plus a dusting of Parmesan cheese, if you like.

Winter lentil soup

4leeks, white and light green parts only

1bunch kale

1tablespoon olive oil

128-ounce can whole tomatoes, drained

6cups water

2sweet potatoes, peeled and cut into 1/2-inch dice

1/2cup brown lentils

1tablespoon fresh thyme leaves

2teaspoons kosher salt

1/4teaspoon black pepper

12fresh basil leaves (optional)

1/4cup (1 ounce) grated Parmesan (optional)

Slice each leek in half lengthwise, then slice each half into 1/4-inch-thick half-moons (about 2 cups). Place in a large bowl of cold water and swish to remove any grit. Drain and pat dry.

Remove the stems from the kale. Stack the leaves on top of one another and slice them crosswise into 1/2-inch-wide strips; you’ll need 3 cups.

Heat the oil in a saucepan over medium heat. Add the leeks and cook for 3 minutes. Add the tomatoes and cook, breaking them up with a spoon, for 5 minutes. Add the water and bring to a boil. Stir in the kale, sweet potatoes, lentils, thyme, salt, pepper, and basil (if using). Simmer until the lentils are tender, about 30 minutes. Spoon into individual bowls. Sprinkle with the Parmesan (if using).

Makes 6 servings.