Pasta with Lentils and Arugula

• 2 tablespoons olive oil
• 2 large onions, halved and thinly sliced (4 cups)
• Coarse salt and fresh ground pepper
• 12 ounces plum tomatoes, cored and diced (about 2 cups)
• 3/4 cup lentils, picked over and rinsed
• 12 ounces orecchiette pasta
• 1 bunch (8 ounces) arugula, stemmed and coarsely chopped
• 1/2 cup finely grated Parmesan cheese, plus more for serving (optional)

1. Heat the oil in a large skillet over medium-low heat.
2. Add the onions and 1/2 teaspoon salt; cover, and cook until the onions wilt, about 20 minutes.
3. Uncover; raise the heat to medium.
4. Cook, stirring often, until the onions are dark brown, 20 to 25 minutes more.
5. Add 1/4 cup water; stir to loosen any browned bits from the pan.
6. Stir in the tomatoes; remove from the heat.
7. Meanwhile, in a medium saucepan, cover the lentils with water by 1 inch.
8. Bring to a simmer.
9. Cover; cook until the lentils are tender but still holding their shape, 15 to 20 minutes.
10. Drain; stir into the onion mixture.
11. Season with salt and pepper.
12. In a pot of salted water, cook the pasta until al dente according to the package instructions.
13. Reserve 1 cup of the pasta water; drain the pasta, and return it to the pot.
14. Add the lentil mixture, arugula, cheese, and reserved pasta water; toss.
15. Season with salt and pepper.
16. Serve with more cheese, if desired.
17. Before using, always wash arugula well in several changes of cold water, until you no longer see any grit in the bottom of the bowl.

olive oil, onions, salt, tomatoes, lentils, pasta, arugula, parmesan cheese

Taken from www.epicurious.com/recipes/food/views/pasta-with-lentils-and-arugula-383357 (may not work)