Preheat your oven to 400°F (200°C).

Optionally line your baking dish with parchment paper or lightly grease it with butter or oil.

Pat the mahi mahi fillets dry, then place them in the prepared baking dish without overlapping.

Whisk together melted butter (or olive oil) with freshly squeezed lemon juice and pour it over the fish.

Combine garlic powder, onion powder, dried oregano, dried thyme, black pepper, paprika, red pepper flakes, and sea salt in a bowl and mix well.

Sprinkle the seasoning mixture evenly over the mahi mahi fillets.

Thinly slice the second lemon and arrange the slices over the seasoned mahi mahi fillets.

Bake for 12-18 minutes until the fish is opaque and flakes easily with a fork.

Remove from the oven and garnish with freshly chopped parsley before serving.