I have wanted to try cooking “grouper” at home since I tried it decades ago at a Club Med in Cancun. Since then I’ve learned a lot about seafood shenanigans and “good” and “bad” lists, but when I saw these yesterday
I’d KISS and let the fish speak for itself (can fish talk?). Butter, white wine, lemon, maybe capers and fresh parsley - the piccata treatment practically lends itself to a nice filet o’fish.
I’d likely grill or broil. A Cajun rub might also work well on the fish. Then I’d just add a squeeze of lemon over the finished dish.
Season the fish with a pinch of turmeric, chilli powder, and salt and set aside while you make the curry. Add the fish only at the very end when the curry is completely done, cook for a few minutes (flip once if you can manage, otherwise just submerge it) till just done. Best with rice.
Try one of these — her recipes are generally reliable. (You can sub coconut milk for grated or dried coconut anywhere, and feel feee to cut back chilli and simplify anything else too, it generally works out even with half the stuff — I made the third one here).
I would make a paste of oil, salt, minced green onions and minced ginger, slather it on the steak, and steam it, Chinese-style. Scatter some cilantro over it when it’s done.
Lemon and egg, yes, whipped up into a foam. I use it sparingly for fish and vegetables, so it’s probably not something that I’d ladle on thick. The ratio is 1/2 lemon per egg. I squeeze the lemon into a straight-sided coffee mug with the egg, and foam it using an immersion blender.
As another idea - you could make a mango/ginger salsa - Caribbean flair - mango, red onion, ginger, lime juice, cilantro, jalapeno/serrano to your spice liking, can add diced tomato if you like too.
I would personally go in a different direction. Grouper is sweet and mild (assuming that IS grouper… it’s pinker than I remember). I like it simply seasoned and sauteed until just done with (preferably browned) butter. Not too high heat. Serve with a squeeze of lemon. Or it’s also very good battered and fried (we make it camping and use bagged beer batter mix. Not sure that works as well for steaks.
— I made the third one 
