Pat the mahi mahi fillets dry on both sides (critical for that sear). Season both sides with salt, pepper, garlic powder, and paprika.

Heat 2 tablespoon olive oil and 2 tablespoon butter in a large skillet over medium-high heat. Sear fillets in two batches if needed (don't overcrowd the pan). Cook each fillet for about 3–4 minutes per side, until golden, lightly crisped, and just opaque in the center (internal temp around 137°F). Remove fish and set aside on a plate loosely tented with foil.

In the same skillet, lower the heat to medium. Add 4 tablespoon butter and let it melt. Add minced garlic and sauté 30–60 seconds until fragrant. Stir in lemon zest, lemon juice, and parsley. Let it bubble gently for 1 minute. Taste and season with a bit more salt, pepper, or chili flakes if desired.

Place mahi mahi on plates or a platter. Spoon the lemon garlic butter sauce generously over the top. Garnish with extra parsley, a squeeze of fresh lemon, and serve immediately.