Mix together pork, fennel seed, sage, salt, and pepper. Divide into 8 equal portions. Form a patty in your hand with the first portion. Flatten patty, place egg inside, and keep rolling egg and meat in the palms of your hands, until a thin layer of meat coats the eggs. Repeat this procedure until all the eggs are coated with pork mixture. Chill 20 minutes.
Dredge chilled, coated eggs first in bread crumbs, then in eggs and bread crumbs again. Chill 15 minutes.
Preheat oven to 375 degrees F.
Heat oil in a large stockpot or saucepan to deep fry temperature (350 degrees F). Fry eggs, 2 or 3 at a time, until golden brown, 3 to 5 minutes. Drain on paper towels. Transfer to a roasting pan and bake 10 minutes. To serve, arrange a bed of Watercress Salad on each serving plate. Slice eggs in half and place 4 halves on top of each salad. Garnish with tomato slices and dollops of Horseradish and Mustard and Mayonnaise for dipping. Serve while eggs are warm.
Whisk together olive oil, lemon juice, salt, and pepper in a bowl. Tear watercress into bite sized pieces and toss with dressing. Reserve in refrigerator.
Blend ingredients together and refrigerate until ready to use.