Tuna with Braised Onions (Atún Encebollado) Recipe

Tuna with Braised Onions (Atún Encebollado)

A pretty simple and tasty dish served in small “cazuelas” in almost every tapas bar in Spain. I like to add a touch of salsa verde on top of it. Not traditional but downright delicious.

Serve with buttered potatoes or with a nice country bread to mop the sauces.

Servings: 4

Time: 40 minutes


Tuna and Onions:

  • 1/4 cup (60 ml) extra virgin olive oil + 1 Tbsp
  • 2 large yellow onions, thinly sliced
  • 4 garlic cloves, thinly sliced
  • 2 bay leaves
  • 1/2 tsp dried oregano, or to taste
  • 1 tsp Spanish smoked paprika, or to taste
  • salt and freshly ground pepper
  • 1/2 cup (120 ml) sherry or dry white wine
  • 1 cup (240 ml) fish or vegetable stock, more if needed
  • 2 Tbsp white vinegar
  • 1 lb (500 g) fresh tuna, cut into 2 inch pieces

Salsa Verde:

  • 1 cup (28 g) flat-leaf parsley, roughly chopped
  • 1/2 cup (120 ml) extra virgin olive oil, plus more if needed
  • 3 garlic cloves, finely minced
  • 6 green olives, pitted and chopped (optional)
  • 4 anchovies fillets, rinsed, drained and finely chopped
  • 1 Tbsp capers rinsed, dried and chopped
  • 1/4 cup (16 g) thinly sliced scallions plus more for for garnish
  • zest and juice of 1 dewaxed organic lemon or more to taste
  • pinch of red pepper flakes
  • salt and freshly ground pepper


Add tuna, 1 tablespoon olive oil, salt and pepper to a bowl. Coat tuna well with the oil mix and refrigerate.

Next start making the salsa verde. Pour 1/2 cup (120 ml) olive oil into a small bowl. Add chopped parsley, garlic, olives (optional), anchovies, capers, scallions, lemon juice and zest, and red pepper flakes. Stir well and season to taste with salt and pepper. If the sauce is too thick for your taste, thin it up with more olive oil. Set aside and let flavors mingle while you prepare the rest of the dish.

Heat the remaining olive oil in a large skillet over medium heat. Add onions, garlic, bay leaves, oregano and Spanish smoked paprika. Cook for about 5 minutes or until onions start to get golden, stirring once in a while. Add the sherry or dry white wine and cook it until reduced to half. Add stock and continue cooking stirring occasionally. Do not let onions get too brown. If necessary, reduce the heat a bit more. Total cooking time should be around 25 minutes. Onions should be soft. Add the white balsamic vinegar and cook it for 1 minute longer. Adjust the seasonings. If sauce seems too dense, or there is not enough liquid left for braising the tuna, add a bit more stock. Keep it over low simmering.

Heat another skillet over high heat. Add oiled tuna pieces and sear them for 1 minute on each side. Tuna should be undercooked. Remove tune from skillet and immediately transfer it to the onion pan. Arrange tuna pieces in a single layer. Distribute some of the of the onions and sauce over the fish and cook it over low heat for 3 minutes longer, if you like your tuna well-done. If you prefer it medium rare, serve it immediately.

The salsa verde is optional, but adds a bit of spiciness to sweet onions.

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