Adapted from BONAPETIT.COM
cup mirin (sweet Japanese rice wine)
cup soy sauce
tablespoon vegetable oil, plus more if needed
6-ounce skin-on, boneless salmon fillets (about 1 inch thick)
Sansho powder (for serving; optional)
Sansho powder, made from the ground berries of the prickly ash tree, can be found at Japanese markets and online.
Combine sake, mirin, and soy sauce in a small bowl; set teriyaki sauce aside. Heat 1 Tbsp. oil in a large skillet over medium-high. Season salmon lightly with salt. Working in batches and adding more oil if needed, cook, skin side down, until skin is brown and crisp, about 4 minutes. Turn and cook until other side is just beginning to brown, about 2 minutes. Transfer to a plate. Pour off fat in skillet. Bring teriyaki sauce to a boil in skillet over medium heat. Cook until reduced by two-thirds, about 4 minutes. Add salmon, skin side up, and cook, spooning sauce over, until sauce is syrupy and salmon is just cooked through, about 2 minutes. Serve sprinkled with sansho powder, if desired.