Combine lentils with 2 cups of the broth in a small saucepan. Bring to a boil, reduce heat, cover and simmer for 30 minutes or until lentils are tender.
Meanwhile, wash kale and remove woody stems. Slice leaves into thin strips, set aside. Mince ham and set aside.
Heat olive oil in a wide skillet and add onion and garlic. Cook over medium heat about 10 minutes, then add cumin, red pepper flakes, kale and ham. Stir about 3 minutes, until kale is limp and reduced in size. Add cooked lentils and remaining broth. Cover and cook until tender. Season with salt and pepper.
Meanwhile, bring a large pot of water to a boil. Add spaghetti and cook until al dente (cooked but a little firm to the bite), about 8 minutes. Drain well and put in a large bowl. Top with lentil mixture and toss. Sprinkle with cheese and serve. Serves 4-6. Serve with bread or rolls.