Preheat oven to 350 degrees. Thinly slice the taro root and place on a roasting pan. Brush with clarified butter. Sprinkle with thyme, garlic and salt and pepper. Bake in oven until golden brown. Fry scallops in sesame oil. Sear the tuna on all 4 sides and let rest for 35 minutes.
Place chopped mushrooms in a roasting pan and pour the sashimi oil on top and roast for approximately 5 minutes in a 400 degree oven.
Bring everything to a boil in a saucepan.
Sea Urchin Sauce:
Bring chicken stock, fish stock and shallot to a boil. Add the soy sauce and reduce. Add heavy cream and butter. Mix in sea urchin.
To Serve: Place 1 taro root chip on top of the plate, place 3 slices of tuna (per person) and 1 whole scallop. Garnish with mushrooms, pour the warm sashimi oil on top of the tuna and scallops. Pour the sea urchin sauce around the tuna and place 1 chip on top.