Step 1: In a blender, combine 1/2 bunch parsley, 3/4 cup extra-virgin olive oil, 2 tablespoons lemon juice, 1 tablespoon black truffle oil, 1/2 minced garlic clove and 1/2 teaspoon sea salt.
Step 2: Blend on a high setting until even. Set aside.
Step 1: In a bowl, mix 1 teaspoon sea salt, 2 teaspoons chopped thyme, 1/2 teaspoon chopped rosemary, 1 teaspoon chopped chives and 1/4 teaspoon ground black peppercorn.
Step 2: Coat 4 (6 to 7 ounce) portions ahi tuna with the herb mixture.
Step 3: Pour 2 tablespoons extra-virgin olive oil in a pan, and sear the tuna lightly on all sides (roughly 10 to 15 seconds on each side for the recommended rare temperature).
Step 4: Slice tuna on an angle, 5 to 6 slices per portion. Drizzle with 1 1/2 tablespoons of the parsley emulsion per portion.