Wash and remove the tough stalks from the greens. Slice the greens into ribbons about 1 x 2 inches.

Heat olive oil in a large saucepan on medium high heat. Toss in the onions and cook for about 5 minutes, or until the onions are beginning to brown.

Add the greens. And add the pepper, salt, water, and, if using, the liquid smoke. Bring to a boil, stir, and reduce heat to medium-low so the greens can simmer.

Cover and simmer about 45 minutes, stirring from time to time. Add a bit more water if needed to keep the greens from sticking to the pan.