Generously season both sides of each fillet with salt and lemon pepper. Set aside.

Thinly slice one lemon and juice the other lemon into a small bowl so that you have approximately 4 tablespoons of fresh lemon juice. Mince the garlic and set aside.

Pan sear the mahi mahi. Add the olive oil to a large skillet set over medium-high heat. Once the olive oil is nice and hot, carefully add each fillet. Sear, undisturbed, until nicely golden brown on the bottom, and the sides are cooked just past halfway up the fillets, about 4 minutes depending on the thickness of your fish (the fish is cooked when it's no long opaque-looking).

In the same skillet (or in a new one), heat the butter, lemon juice, and lemon slices over medium heat. Heat until the butter is melted and just starting to bubble. Stir in the garlic, reduce heat to low, and continue to cook for 1 minute, or until the garlic is lightly golden. Stir in the fresh minced parsley and drained capers (optional).

Combine and serve. Spoon the garlic butter sauce over the mahi-mahi and serve immediately.