Pasta with kale, lentils & caramelized onions

250g green lentils (I used black Beluga lentils instead)
water
3/4 teaspoon salt
6 tablespoons extra-virgin olive oil
2 large onions, finely sliced
1-2 tablespoon good quality runny honey
1/4 teaspoon black pepper
450g kale (or you can go for cavolo negro a.k.a. black cabbage)
250g pasta of your preference

While lentils simmer- I am lazy so went for a packet of Merchant Gourmet- heat oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then sauté onion with pepper, 1/2 teaspoon salt and honey, stirring for a couple of minutes. Reduce heat to low and cook until soft and golden.
While onion cooks, cut out and discard stems and inside ribs from kale. Steam kale until just tender, 5 to 8 minutes. Transfer kale with tongs to a colander to drain, pressing lightly. Keep the water at a boil in the pot covered.
Coarsely chop kale and add to onion along with lentils, then simmer, stirring, 1 minute. Season with salt and pepper.
Add pasta to kale-cooking liquid and boil following package instructions. Drain pasta. Toss everything together. Serve with a bit of Parmesan cheese.