This snapper is elegant, luscious, yet simple to prepare thanks to the miso butter, which caramelizes into an umami-rich pan sauce. Served with a bright herb salad, it's a dish that's both refreshing and melt-in-your-mouth.
Preheat oven to 450 degrees F. Heat an oven-safe saute pan over medium heat. Season fillets with josher salt on both sides. Turn heat to high and add 3 tablespoons Miso Butter to the preheated pan; when it has melted, place fish on top of the butter, skin-side up, in an even layer. Move the fish around in the butter as it starts to bubble and the miso begins to caramelize, 2 minutes. Place pan in the oven to finish cooking fish, about 2-4 minutes, depending on thickness. Meanwhile, make the Herb Salad. (Note: If using a convection oven, place skillet on the middle rack. If using a conventional oven, place skillet on lower rack.)
In a small saucepan over high heat, bring sake and mirin to a boil to burn off the alcohol. Once boiling, add sugar, stir, and continue boiling until the sugar has completely dissolved and the liquid is translucent. Turn off heat and stir in miso.
In the bowl of a stand mixer fitted with a whisk attachment, add butter. Whisk at medium speed until butter is fluffy and pale yellow, 1 minute. Continuing on medium speed, slowly add the miso mixture in a steady stream to combine. Turn off motor, scrape down the sides of the bowl, and continue mixing again, just until incorporated. Pour Miso Butter into a bowl and set aside. Makes about 2 cups. (Store in a lidded container in the refrigerator for up to 1 month.)
In a bowl, combine Thai basil, mint, chervil, dill, and celery leaves (or a fresh herb combination of your choosing). Set aside.
Remove fish from oven: it’s fully cooked when opaque throughout, and should flake when touched. The Miso Butter will be brown and caramelized in the pan. Flip the fish onto a serving plate, skin-side up, and finish with a sprinkle of flaky salt. Pan sauce: To the caramelized butter in the hot pan, add 1 tablespoon of fresh Miso Butter and stir to combine. Spoon pan sauce over the fish. Add ponzu to the Herb Salad, toss, and serve with the fish.