Start by preheating your oven to 400°F (200°C). Line a baking sheet with parchment paper to keep cleanup quick and simple while preventing sticking.

Use paper towels to gently blot any excess moisture from the mahi-mahi fillets—this step is crucial to achieving a clean, tender finish. Lightly season both sides of each fillet with salt and freshly ground black pepper, ensuring an even distribution of flavor.

Arrange the seasoned fillets in a single layer on the prepared baking sheet. Drizzle the olive oil evenly over the surface of the fish, allowing it to seep slightly underneath. Scatter the minced garlic (if using) and chopped herbs—parsley and dill—across the top, ensuring each bite is infused with aromatic freshness.

Squeeze the juice from one half of the lemon directly over the fillets, coating them in a bright citrus layer. Then, place the thin lemon slices on or around the fish to roast gently during baking, adding both flavor and visual appeal.

Slide the tray into the preheated oven and bake for 12 to 18 minutes. The fillets are done when the flesh turns opaque and easily flakes with a fork—be careful not to overcook, as mahi-mahi can dry out quickly.

Transfer the cooked fish to serving plates using a spatula. Garnish with extra herbs or fresh lemon wedges, if desired. Serve immediately with your favorite accompaniments such as roasted vegetables, seasoned quinoa, or a crisp green salad.