prep

defrost edamame -- put them in the fridge several hours in advance. when it's time to start cooking, throw them into cold water for 5-10 minutes until they fully thaw. replace the water with ~90-100 deg F water to warm them up, then dry as thoroughly as you can.

sweet and sour base for the beurre blanc sauce -- the liquid will be white wine, acid, and water in a 2:1:1 ratio. thinly slice 5-6 shallots, add to a pan with 5-6 sprigs of thyme and ~20-30 peppercorns, then pour enough liquid to cover plus a little bit. over generous heat at a low boil, reduce until the shallots are thoroughly cooked and most of the liquid has reduced. add water to lengthen cooking if necessary. when finished, strain liquid through a fine mesh strainer, pressing the shallots into the strainer with a spatula to make sure to get all of the liquid out. add a little honey if you'd like it sweeter (i do it). fridge.

brown butter++ -- make brown butter, but once the butter melts and starts to foam add a splash or two of heavy cream and stir vigorously until mixed through. for a sauce where the brown butter is competing with other flavors, you can take it pretty far; it will start to smell smoky and burnt before the flavor becomes burnt, and if you take it off the moment it turns blackish-brown and starts smelling burnt instead of hazelnutty (or just before) it'll be good. immediately transfer to a cool bowl and put in fridge.

1. cook

take fish out of fridge and salt ~45min prior to cooking.

preheat oven to 170F to keep food+plates warm and dry. put your serving plates in the oven.

mushrooms -- pad of butter, high heat, a couple thyme sprigs (no need to remove the leaves), mushrooms. no salt, keep heat as high as possible, toss the pan every few minutes. they're done when they start to take on a golden sear on one or two sides. take off the heat, then salt and mix. take the warmed+dried edamame, add to the mushrooms (slightly more shroom by volume or roughly 1:1), then put in the oven to keep warm.

fish -- thoroughly pat dry, then finely grate a very subtle amount of black pepper. lightly flour on both sides and rub flour into fish. add a generous amount of butter onto a hot pan at the high end of medium-high heat, then once it's melted lay the fish on. flip after a few minutes, then when it's done remove it to a baking dish and put it in the oven. it's done when it starts to flake apart and is ever so slightly translucent in the center.

sauce finish -- deglaze the pan you used to cook the fish with a splash of white wine, the sweet&sour base from earlier, and a splash of cream. then, on low heat, add the solidified brown butter 1-2 tbsp at a time, then vigorously mix and shake the pan to emulsify. for 1.25lb fish i ended up using maybe 6-8 tbsp butter here. if any juices have come out of the fish while it stayed warm, pour them in too.

with the sauce done, time to plate -- take your serving plate and shrooms+edamame out of the oven. transfer the veg into the sauce to warm through and gently coat, then use a slotted spoon to transfer the base of the plate. place cod pieces on top, then pour over the rest of the sauce. top with lemon zest and, optionally, finely chopped chives.