make sauce first. heat rice wine vinegar in small saucepan until boiling.

heat one half tsp. oil over high heat in saute pan, look for light smoke, then saute tuna on one side for approximately 2 mimuted until golden.one side for

whisk butter, a few pieces at a time.

add lemon zest, juice of one half lemon, thyme leaves, and salt to taste.

set aside in warm spot

sprinkle and press pepper evenly on both sides of tuna, and sprinkle with a little salt.

heat one half tsp. oil over high heat in saute pan, look for light smoke, then saute tuna on one side for approximately 2 minutes until golden

add remaining oil, flip Tuna, and cook 1 or 2 minutes more

pour sauce over fish, and squeeze on remaining lemon juice.