12 large leaves spinach, tough stems removed
8 small slices pumpernickel bread or 4 large slices, cut in half, toasted
4 slices Swiss cheese
¼ tsp. freshly ground pepper
¼ tsp. salt
⅓ cup finely diced ham
1 pound ground chicken
1½ tsp. finely chopped fresh thyme, divided
5 tbsp. finely chopped shallot, divided
¼ cup low-fat mayonnaise