Ponzu Sauce:
juice of one lemon
juice of one lime
1 tablespoon rice vinegar
3 tablespoons soy sauce
1 dash of Mirin (rice wine vinegar)
Mustard Sauce:
1 minced shallot
6 tablespoons butter, divided
1/4 cup white wine
juice of one lime
2 tablespoon dry mustard powder
3 tablespoons whipping cream
1 pound of tuna cut into 2 inch square strips cover; one side with white and black sesame seeds
Combine all ingredients for the Ponzu Sauce; set aside.
Heat a saute pan and sweat shallots in a little butter. Deglaze with white wine and lime juice. Reduce by 2/3 and add mustard powder and whipping cream. Further reduce by 25 percent.
Remove from heat and whisk in remainder of butter.
Heat another saute pan until smoking hot. Add a little peanut oil. Sear tuna pieces on all four sides for 40 seconds. Take out of pan and cover with Ponzu sauce and serve Mustard Sauce on the side, enjoy!