2 Place tuna into a clean cast iron skillet and briefly sear for approximately 20 seconds. Blacken on all sides; cook fish RARE in temperature.
3 When the Ahi Tuna is seared of, place on cutting board and slice into 8 even pieces with a very sharp knife. Slide the knife under the tuna and place on the platter.
4 Using a squeeze bottle, drizzle 1/2 ounce volume of mustard sauce around the tuna.
5 To make the mustard sauce, measure out dry mustard and Dijon mustard and mix well into smooth paste. Slowly add soy sauce and whip to incorporate into mustard paste. When all soy sauce is added, slowly add (non alcoholic) beer and whip well. Make sure the mustard paste is fully incorporated.