Heat the oil in a large deep pot to 325 degrees F.
Season the cornmeal with salt, pepper, cayenne, and paprika and mix well. Dredge the oysters in the seasoned cornmeal, shaking off any excess.
Slice the tomatoes into thin slices. Season tomato slices and watercress with some of the vinaigrette, and salt and pepper.
Toast the pullman bread. Spread bread with truffle mayonnaise and place tomato and watercress on each piece of bread.
Flash-fry oysters in peanut oil for about 30 seconds, or until golden brown and season with salt and pepper. Place tomato-watercress bread and oysters on each of 4 plates. Garnish with black truffle slices and truffle oil.
Combine ingredients, except for oils in a blender or food processor and mix. With the machine running on low, slowly drizzle in the oils until a mayonnaise consistency develops. Season with salt and pepper.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.