Blackening is a spice crust, not burnt fish. The fish gets dipped in butter, pressed into a heavy spice mix, and hit on ripping-hot steel so the spices toast into a dark crust in about three minutes a side. The flat-top handles this better than a pan because you can get it hotter without filling the kitchen with smoke. Grouper and mahi both take the crust beautifully and cook on the same clock, so they run side by side. Make the slaw and crema first so they're cold and ready.
Both are firm, meaty, and hold together on the steel, which is exactly what a blackened taco wants. They cook on the same clock, so you can run them together and let people pick.
Grouper is a little sweeter and flakes into bigger, softer pieces. Mahi is leaner and firmer with more bite, and it holds a crust slightly better. Cut both into similar-size portions so they finish at the same time.
The cold crunch against hot spiced fish is the entire point of a fish taco. Make both of these first and get them in the fridge so they're properly cold when the fish comes off.
Blackening only works if you're generous. A light dusting gives you seasoned fish; a heavy coat gives you the dark crust you're after. The butter is what makes the spice stick and toast instead of scorch.
This is the whole cook and it's over in about six minutes. The crust forms because the fish sits still on very hot steel. Every time you move it, you break the crust. Grouper and mahi go down together.
Same blackened grouper and mahi, same slaw and crema, built two ways. Both get avocado, pickled onion, cilantro, and a squeeze of lime. Put a little of each fish on both plates so you can taste them against each other.
Break the fish into big flakes rather than shredding it. You want real pieces with crust on them in every bite, and keep the two fish a little separate so you can tell them apart.
Five from the back half of the seventies, when disco owned everything. Bright, loud, built for a fast cook and a table full of tacos. Put it on before the steel is even hot.
Per plate with four corn tortillas. Lauren's bowl version runs roughly 130 cal and 24g carbs lighter without them. Grouper and mahi are both lean, so most of the fat is the butter, crema, and avocado. Ballpark either way.