For the spice mixture: Combine all ingredients in a bowl and set aside.
For the juice mixture: Blend all ingredients except butter and oil until smooth. Add oil and butter to finish. Add warm chicken stock and season to taste.
For the romaine: Over high heat saute romaine ribs in olive oil until tender. Add anchovies and coriander. Finish by tossing with basil and season with lemon juice, salt and pepper.
For the tuna: Season tuna pieces with oil and salt and pepper evenly. Place seasoned tuna in spice mixture and coat evenly. Next, heat oil in a cast iron skillet until very hot. Add tuna and cook to desired doneness and set aside to rest for a couple of minutes. Slice each piece after resting.
Plating: Place braised romaine in center of plate. Next arrange warm tuna slices on top of romaine. Finish plate by drizzling warm juice around the plate. Serve.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Geoffrey Zakarian, Patroon Restaurant, New York, NY