Chef’s Note: You can replace the 2 fillet with 1 large piece of salmon. Once the cooking process is complete, you can place the salmon and sauce in a bowl and shred the salmon into the sauce and use that shredded salmon nitsuke as a topping for tofu salad, as a filling for sushi or even as a filling for burritos, tacos or chirashi sushi.
Heat a medium sized pan on high heat and add in the oil. When the oil lightly smokes, add in the salmon. Sear for 2 minutes and then flip the salmon over, deglaze with the dashi and quickly add in the shoyu, mirin and ginger. Bring the mixture to a quick boil and then reduce the heat to medium and simmer for 2 minutes. Remove the salmon from the pan and place on a serving plate or platter.
Place the pan back on the heat and reduce the remaining liquid in the pan by half to concentrate the flavor and then pour the sauce over the salmon. Serve immediately.