Boil the eggs by placing them in a single layer on the bottom of a medium pot and covering them with cold water. Over high heat, bring the eggs to a rolling boil. Once boiling, remove from heat and let the eggs stand in the water for 10-12 minutes. Drain and rinse the eggs with cold water until they are cold enough to handle.
Slice the eggs in half lengthwise; removing the yolks. Set whites aside.
In a small mixing bowl, smash the egg yolks. Combine with mayonnaise, ground mustard, vinegar and tarragon.
Stir in cheese and ham.
Spoon mixture into egg white halves. Garnish with fresh parsley.
