Preheat the oven to 400 degrees F. Pull the swordfish out of the refrigerator and allow it to come to room temperature while you make the shallots and the sauce.
For the pickled shallots: Separate the shallots into little rings. Put them in a small saucepan, add the rice vinegar and 1/4 cup of water, and set over medium heat making sure the shallots are covered by the liquid. Bring to a boil. Once it's bubbling, turn the heat off and set aside until you're ready to serve. The pickling will bring out a natural pink hue in the shallots; beautiful!
For the "mole": Grind the mustard seeds and cumin seeds to a fine powder in a mortar and pestle. Pour into a bowl with the ginger, ancho chile powder, rice vinegar, mirin, honey, sriracha and honey. Whisk together until smooth. Taste for seasoning and adjust as necessary.
Set a large cast-iron or other heavy-bottomed, ovenproof skillet over medium-high heat until lightly smoking.
Sprinkle the swordfish with salt. Add the swordfish to the skillet. Cook until browned, about 3 minutes on one side. Quickly, flip the steaks and smear with a little "mole". Put the pan in the oven and cook the fish until a thermometer inserted into the middle of the fish registers 125 degrees F, 5 to 7 minutes.
While the fish is cooking in the oven, drain the shallots and place in a small bowl. Rip the cilantro with your hands into the bowl, then drizzle with a little extra-virgin olive oil, salt and pepper. Toss together and taste for seasoning.
When the fish is cooked (remember that it will keep cooking even when it's out of the oven) remove to a platter. Add the butter to the skillet, scraping up any caramelized bits stuck on the bottom of the skillet. Stir in the remaining "mole" and cook until hot and bubbly. Pour over the swordfish steaks. Top with a handful of the pickled shallots and serve immediately!
*Try to buy domestic swordfish that is harpoon or handline caught. Swordfish caught on long lines or in driftnets tend to also catch endangered sea turtles and sharks!
Recipe courtesy of Aarti Sequeira