Bring two quarts of water to boil in large pot. Add salt, and greens and stir until wilted. Cover and cook just until tender, about 8 minutes. Drain in colander, and rinse thoroughly in cold water. Gently squeeze excess water from greens and pat dry with paper towels (can do ahead through this step - leave greens loosely wrapped in paper towels at room temperature).
In large sauté pan, melt butter over medium heat. Add greens and stir to coat. Add cream and nutmeg, cover and cook just until greens are heated through. Season with salt and pepper. 4 servings.
*Tough center stems can be cut from kale, or if you prefer, hold the base of the stem firmly in one hand, and strip the kale off the stem. Wash in several changes of cold water to remove any dirt or grit.
**To reduce fat in this recipe, non-fat half and half can be substituted for cream.