Soak the trotters in water in the fridge overnight.
Debone the pig trotters. This one sentence hides a lot of work. Look up videos how to do it.
Preheat the oven to 180°C. In a large lidded casserole dish, gently fry the onion, celery and carrot for a couple of minutes. Add the white wine to deglaze, and reduce until sticky. Add the trotter skin side down, add the stock and herbs, cover and bake in the oven for 2.5 hours.
Meanwhile, make the chicken mousse. Blitz the egg, chicken and salt together until smooth, and then drizzle in the cream while still blending. Push through a sieve and refrigerate until needed.
Soak the porcini in boiling water to refresh. In a pan fry the diced onion and tofu until lightly coloured. Combine with half the porcini and cool slightly. When cooled, mix enough mousse into it until bound. Refrigerate until needed.
Get the sauce started. In a pan start frying the turkey legs until starting to brown, and then add mushrooms, shallots and garlic. Fry gently until starting to soften, add the herbs and deglaze with the vinegar. When reduced to almost nothing repeat with Marsala. Then add the chicken stock. Simmer for 20 minutes, and then pass through a muslin cloth. Keep the sauce in a saucepan covered ready for serving. Before serving add a few drops each of lemon and cream, then season to taste.
For the mash simmer the potatoes for 10 minutes until tender. Drain really well then blitz in a food processor with the butter and cream until smooth.
For the shallots wrap in tin foil with butter and salt for 30 minutes until tender. The skins should slip off easily.
The trotter should be ready now so remove from the oven, discarding the vegetables. Take your mousse mix and force into the skin up to the toe bones. Place on aluminium foil and wrap tightly into a sausage. Poach in simmering water for 12 minutes.
Serve the trotter unwrapped from the foil, with mashed potato, roasted onions, dot with remaining porcini and pour over the sauce.
Video
Notes
You are supposed to use sweetbreads in place of the tofu.