• 4 salmon fillets, about 6 oz [170 g] each, skin and pin bones removed

Sweet Vinegar Sauce

• 1/2 cup [120 ml] soy sauce
• 1/4 cup [60 ml] distilled white vinegar
• 1/4 cup [50 g] sugar
• 4 green onions, including green tops, cut into 1-in [2.5-cm] lengths
• 4 thin slices fresh ginger, peeled and julienned
• 3 cups [720 ml] water
• 3 green onions, including green tops, cut into 1-in [2.5-cm] lengths
• 5 thin slices fresh ginger, peeled

Instructions

1. Remove the salmon from the refrigerator 30 minutes before cooking to bring it to room temperature.
2. To Make the Sauce: In a small bowl, stir together the soy sauce, vinegar, and sugar until the sugar is dissolved. Stir in the 4 green onions and julienned ginger. Set aside.
3. In a sauté pan just large enough to hold the salmon fillets in a single layer, combine the water, 3 green onions, and sliced ginger. Bring to a boil over medium heat, turn the heat to medium-low, and simmer for 5 minutes. Using a spatula, carefully slip the salmon into the pan. (The salmon should be completely submerged in the poaching liquid. If it isn’t, add a bit more water.) Cover the pan and poach the salmon for 5 minutes.
4. Again using the spatula, lift the salmon to a plate. Carefully drain off almost all the poaching liquid from the pan, leaving only 1/4 cup [60 ml] in the pan. Remove and discard the green onions and ginger from the pan. Return the pan to medium-low heat and add the vinegar sauce. Bring to a simmer, stirring occasionally. Slip the salmon back into the pan and baste with the sauce. Continue to braise the salmon, basting frequently, until almost opaque throughout, or an instant-read thermometer inserted into the center registers 125°F  [52°C] or a little above, about 8 minutes. The sauce will have reduced and thickened a little.
5. Transfer the salmon to warmed dinner plates or shallow pasta bowls. Spoon the sauce around the fillets, dividing it evenly. Serve immediately.