Pat the mahi-mahi fillets dry with paper towels. Trim any thin edges so the fillets are an even thickness (this helps even cooking). Score skin lightly if present to prevent curling.

Make blackening seasoning

In a small bowl combine paprika, smoked paprika, garlic powder, onion powder, dried thyme, dried oregano, cayenne pepper, black pepper, and kosher salt. Mix thoroughly so the spices are evenly distributed.

Season fillets

Brush both sides of each fillet lightly with olive oil (about 1/2 tbs per side). Generously coat both sides of each fillet with the blackening spice mix, pressing lightly so the spices adhere. Let rest at room temperature for 10 minutes while you heat the pan.

Heat skillet

Place a heavy-bottomed skillet (cast iron preferred) over medium-high to high heat and let it get very hot — about 3–5 minutes. The pan should be smoking slightly when ready. Add the remaining 1 tbs of olive oil and swirl to coat.

Blacken the fish

Carefully place fillets, spice side down, into the hot skillet. Do not overcrowd; cook in two batches if necessary. Sear without moving for 2–3 minutes, until a dark crust forms. Flip and cook the second side 2–3 minutes more, until the internal temperature reaches 135–140°F (57–60°C) for moist, just-cooked fish. Thicker fillets may need up to 4 minutes per side. Remove fillets to a warm plate and tent loosely with foil to rest for 3–4 minutes.

Pan sauce (optional)

Make sauce

With the pan still hot and any browned bits present, reduce heat to medium. Add the minced shallot and sauté for 30–45 seconds until fragrant (do not burn). Add the white wine or fish stock and scrape up browned bits with a spatula. Let reduce for 1 minute, then whisk in the butter one tablespoon at a time to create a glossy sauce. Stir in lemon juice and chopped parsley, taste and adjust with a pinch of salt or more lemon if needed.

Finish

Spoon the pan sauce over the rested fillets just before serving or serve on the side.

To serve (optional)

Plate the blackened mahi-mahi with lemon wedges and a sprinkle of microgreens or chopped parsley. Serve immediately with your choice of sides (rice, grilled vegetables, or a simple salad).