In a small bowl, mix together the rosemary, mayonnaise, mustard, salt and pepper. Rub the pork butt all over with this mixture. Place in the oven and roast for about 2 1/2 hours.
In the last half hour of cooking add apples and onion to the pan and toss in some of the pan juices. The pork should be 175 degrees when done. Let rest for 20 minutes before slicing. Serve with the apples and onions.
For the salad: Place the kale in a large bowl and sprinkle with some salt. Begin to massage the kale gently, continuing until it softens and wilts. Add the spinach, onion and orange. In a small bowl, whisk together the vinegar, olive oil and honey. Toss the salad with dressing.