For the emulsion: In a saute pan, heat the olive oil. When the pan is smoking hot, saute the portobello, shallots, garlic, and tomatoes, for 2 to 3 minutes. Add the veal reduction. Simmer for 2 to 3 minutes or until the mixture is almost dry. Season with salt and pepper. Remove from the heat and cool completely. In a food processor, combine the mushroom mixture, mayonnaise, chopped truffle, truffle oil, and lemon juice together. *If the mixture is too thin add additional mayonnaise. Season with salt and pepper. For the potatoes: In a pot of salted water, bring the potatoes up to a boil and cook for 8 to 10 minutes or until the potatoes are fork tender. Remove from water and drain. To assemble, smash each potato with the back of a kitchen spoon. Season each potato with salt and pepper. Spoon a small amount of the truffle emulsion on the bottom of the plate and dirty the rim. Place two of the smashed potatoes directly on the sauce. Sprinkle with the grated cheese. Shave the truffle over the top of the potatoes. Drizzle the truffle oil over the entire plate. Garnish with the caviar, long chives, chopped chives and black pepper.