Pasta with Lentils and Kale

1.Simmer lentils in water (2 cups) with 1/8 teaspoon salt in a small saucepan, uncovered, adding more water if necessary to keep lentils barely covered, until tender but not falling apart, 20 to 30 minutes.

2.Remove from heat and season with salt.

3.While lentils simmer, heat 3 tablespoons oil in a 12-inch heavy skillet over medium-high heat until it shimmers, then sauté onion with 1/4 teaspoon pepper and 1/2 teaspoon salt, stirring, 1 minute.

4.Reduce heat to low and cook, covered, stirring occasionally, until onions are soft and golden (stir more frequently toward end of cooking), about 20 minutes.

5.Remove lid and increase heat to medium, then cook, stirring frequently, until onion is golden brown, 5 to 10 minutes more.

6.Stir in lentils, including their liquid, and simmer, scraping up any brown bits, 1 minute.

7.Season with salt and pepper.

8.While onion cooks, cut out and discard stems and center ribs from kale and coarsely chop leaves.

9.Start cooking pasta in a 6- to 8-quart pot of well-salted boiling water, according to package instructions.

10.Seven minutes before pasta is finished cooking, stir in kale and boil, uncovered, until pasta is al dente.

11.Reserve about 1 cup pasta-cooking liquid, then drain pasta and kale in a colander.

12.Add pasta mixture to lentils along with about 1/3 cup of pasta-cooking liquid (or enough to keep pasta moist) and cook over medium-high heat, tossing, 1 minute.

13.Season with salt and pepper and drizzle with remaining 2 tablespoons oil.