Season the swordfish with the salt and some pepper. Spread some flour on a plate.

Lightly dredge the swordfish on all sides in the flour, tapping off the excess. Reserve the flour.

When the oil is hot, gently lay the swordfish in the skillet, and cook until it is brown on both sides and just cooked through – about 2 minutes per side, depending on the thickness of the fish.

Remote it to a platter, cover it with foil, and keep it warm.

Carefully pour out the oil from the skillet, and wipe it clean with a paper towel. Over medium-high heat, add the olive oil.

When the oil is hot, sprinkle in a teaspoon of the reserved flour, and stir to make a paste.

Let the flour toast for a minute, then add the wine, vinegar, and capers.

Bring the liquid to a boil, and cook until the sauce is a light syrup, about 4 minutes.

Off heat, stir in the parsley, and whisk in the butter in pieces until the sauce is emulsified.

Spoon the sauce over the fish, and serve.