For thousands of years, Japanese cooks have used the fermented soybean paste called miso to preserve fish. Now that modern refrigeration is available, they turn to miso not for its preservative qualities but for the sweet and salty flavor it lends. This recipe is based on one in The Japanese Kitchen by Hiroko Shimbo (Harvard Common Press, 2000). Shimbo recommends using saikyo miso— a sweet, white miso made with more rice than soybeans—for a lighter, more refined dish.
- 2 1⁄3 cups miso, preferably white miso
- 1⁄4 cup mirin
- 3 tbsp. sake
- 1 tbsp. peeled fresh ginger, finely chopped
- 1 chile de árbol, stemmed, seeded, and finely chopped
- 4 (8-oz.) boneless skin-on salmon filets
- 1 tbsp. sugar
- 2 egg yolks
- 2 tbsp. frozen chopped spinach
- Sweet pickled ginger, for garnish
- Marinate the salmon: In a bowl, whisk together 2 cups miso, mirin, 1 tbsp. sake, fresh ginger, and chile. Spoon half the miso marinade into the bottom of a shallow dish. Score the skin of the salmon filets on the diagonal with a sharp knife. Lay the filets evenly over the marinade, skin side up, and spoon the remaining marinade over the top, spreading it evenly over the fish. Cover with plastic wrap and let marinate for 2–3 hours at room temperature or up to 8 hours in the refrigerator.
- Meanwhile, make the sauce: Pour water into a medium pot so that it reaches a depth of 2″. Bring to a simmer over medium-low heat. In a small food processor, pulse the sugar and eggs to combine. Add remaining miso, remaining sake, spinach, and 2 tbsp. water. Process until the spinach is finely chopped and the mixture is smooth, about 15 seconds. Transfer the spinach mixture to a medium metal bowl; place over simmering water and cook, whisking constantly, until the sauce thickens and becomes glossy, 8–10 minutes. Transfer sauce to a small bowl and set aside.
- Arrange an oven rack 3″ from the broiler element and heat. Scrape marinade off salmon, brush each filet with 1 tbsp. miso–spinach sauce, and place them on a foil-lined baking sheet, skin side down. Broil for 2 minutes. Turn salmon and continue broiling until the skin crisps and browns, about 2 minutes more. Divide the salmon between 4 plates. Spoon more sauce onto the plates and garnish with pickled ginger slices.