Seared Ahi Tuna with Caramelized Onion Ginger Sauce

This recipe is inspired by our on-board chef Risa, when we chartered a catamaran through the British Virgin Islands. How she delivered dish after delicious dish from that boat galley was amazing…..thank you Risa!


1 tbsp. each of unsalted butter and olive oil

2 large onions finely chopped

1 tbsp. sugar

3 tbsp. apple cider vinegar

1 tbsp. freshly grated ginger

4, 6oz. sushi grade tuna steaks

1/4 cup low sodium soy sauce

1/4 cup each black and white sesame seeds (see below to order)

1/2 tbsp. olive oil

For the caramelized onions and ginger:

In a skillet heat the butter and olive oil over medium high heat.  Add the onions.  Fry until onions turn glossy.  Continue to fry stirring to make sure they cook evenly and don’t stick.  When the onions are turning lightly brown add the sugar and incorporate.  Then add the vinegar and allow to somewhat evaporate.  Remove from the heat and cool slightly before adding the ginger.  Set aside.

For the tuna:

Mix and spread the sesame seeds onto a plate. Place the soy sauce in a shallow dish. Coat the tuna with the soy sauce, then press into the sesame seeds to coat both sides. Heat oil in a heavy skillet over high heat until very hot, being careful not to “burn” the oil.  It should not be smoking. Carefully place the steaks in the pan and sear on each side (approx. 30 seconds).  Tuna will be raw in the center.  Remove from pan and transfer to a cutting board.

For presentation:

With a very sharp knife, slice each tuna steak into 1/2″ slices.  Arrange on a plate.  Spoon over the caramelized onion sauce and serve.

This dish can be served on it’s own with a variety of sides, such as farrow, wild rice or other grain.  Risa served it over a bed of lightly roasted asparagus spears as shown above.  I also like to serve this with a unique dutch Indonesian sauce called Ketjap Manis.  It is a sweet and thick soy sauce with a delicious unique flavor.  Just a drizzle over the tuna is all that is needed.  See my link below to order.