For truffle tartar (makes about 2 cups sauce):
Combine eggs, Dijon, and lemon juice in bowl of a food processor. Blend for 1 minute. With motor running, slowly add truffle oil, then canola oil. Transfer to a mixing bowl. Stir in gherkins and dill. Season with salt.
For hush puppies (makes about 5 dozen):
Melt butter in a small skillet over medium heat. Add cauliflower and cabbage, sauté until golden brown. Season with salt and pepper. Set aside.
Prepare hush puppy batter. Combine flour, cornmeal, baking powder, and salt in a large bowl. In a separate bowl, beat eggs with buttermilk. Mix flour mixture with egg mixture. Stir in cauliflower-cabbage mixture and mashed potato.
Heat fryer to 350° and carefully drop tablespoon-sized drops into fryer. Fry until golden brown and drain on a wire rack. Serve with tartar sauce.