Prepare the Fish: Pat the mahi mahi fillets completely dry with a paper towel. In a shallow dish, mix together the plain flour, salt, and pepper. Lightly dredge each fillet in the flour mixture, shaking off any excess. This thin coating helps create a lovely crust.

Heat the Pan: Place a large, heavy-bottomed frying pan or skillet over a medium-high heat. Add the olive oil. You'll know the pan is ready when the oil shimmers slightly.

Sear the First Side: Carefully place the floured fillets in the hot pan. Don't overcrowd it; cook in batches if necessary. Sear the fish for 3-4 minutes without moving it. I find that resisting the urge to poke or move the fish is key. This allows a beautiful, golden-brown crust to form.

Flip and Finish Cooking: Using a thin fish spatula, flip the fillets over. Cook for another 2-4 minutes, depending on the thickness of your fillets. The fish is cooked when it is opaque all the way through and flakes easily when gently prodded with a fork.

Rest the Fish: Transfer the cooked mahi mahi to a warm plate and set aside.

Start the Sauce: Reduce the heat to medium-low. Add the unsalted butter to the same pan. Allow it to melt and foam, swirling the pan occasionally. It will start to turn a light brown and smell nutty – this should take about 1-2 minutes.

Add Aromatics: Add the minced garlic to the brown butter and cook for about 30-60 seconds, stirring constantly, until it's fragrant. Be careful not to let it burn.

Deglaze and Finish: If using, pour in the white wine to deglaze the pan, scraping up any tasty browned bits from the bottom. Let it bubble and reduce by about half. Stir in the fresh lemon juice and chopped parsley. Taste and add a pinch more salt if you think it needs it.

Serve Immediately: Spoon the warm lemon and garlic butter sauce over the pan seared mahi mahi fillets and serve right away.