Escabeche De Atum (Pickled Tuna)

Place tuna in a single layer in a large skillet. Scatter half the onions and half the garlic over the fish. Drizzle with half the vinegar, add 4 cups water, and season with salt and cayenne pepper. Poach over medium heat until fish flakes easily, about 10 minutes.

Allow tuna to cool in poaching liquid, then transfer to a shallow dish with a slotted spatula. Discard poaching liquid.

Scatter remaining onions and garlic over tuna, add oil and remaining vinegar, cover, and marinate in the refrigerator for at least 3 hours.

Serve at room temperature, garnished with parsley, hard-cooked eggs and olives.