How to Make It
Cut ham into 3/4-inch cubes. Carefully break cheese into 60 small pieces. Cut apple slices into thirds.
Thread cheese, apple, watercress leaves, and ham onto skewers. Stand skewers upright, ham ends down, on a serving plate.
Assemble up to one hour ahead, cover with damp paper towels, and chill. Serve coarse-grain mustard or chutney alongside the skewers.