La Fontanella Tuna alla Favignana

Source: La Fontanella - Phoenix, Arizona (originally from Chicago, Illinois)

4 (1-inch) slices of Ahi tuna
2 large onions
1/2 cup red wine vinegar
1/2 cup white wine
Chopped parsley
1/2 cup olive oil
Sea salt
Extra virgin olive oil
Black pepper

Season tuna with salt and pepper. Slice onion thinly into matchsticks.

Heat large skillet; add oil and onions. Sweat and cook until caramelized golden. Add vinegar and wine. Boil to evaporate alcohol; add tuna. Cook 3 minutes on each side. Keep fish moist, adding water if necessary.