Portuguese Fresh Tuna (Sauce and Marinade)
Family Recipe, a staple once a year when fresh tuna was available in my area. It's pretty spicy, so it is generally served with boiled potatoes which are perfect for soaking up the sauce. The sauce is awesome and stands up to the very meaty fish. For some reason, long lost, my grandmother always asked for the darkest tuna steaks they had. She insisted they were better. Pretty sure my grandmother used lard for frying, my aunt says butter and oil do fine. Any vegetable oil is fine if you don't buy you olive oil by the gallon. Plate the fish with some rice or potatoes (both if you are Portugues).