Begin by rinsing your fish fillet under cold water and patting it dry with paper towels. Rub the fillet with toasted sesame oil, sprinkling it lightly with salt and black pepper to season. Set aside.

Using a sharp knife, julienne the ginger, scallions, and half of the carrot. Thinly slice the onion and the remaining carrot.

In a medium-sized pan, heat olive oil over medium heat. Add the minced garlic and optional shallots, sautéing for 1-2 minutes until fragrant. Stir in the julienned ginger and cook for another minute.

Prepare your steamer basket or pot with a steamer insert. Layer sliced onion and carrot at the bottom, then place the seasoned fish fillet on top. Spread the sautéed ginger mixture over the fish and cover tightly with aluminum foil.

Bring water in the steamer to a boil. Carefully lower the steaming dish into the steamer basket and cover with a lid. Steam for 8-9 minutes until the fish is opaque and flakes easily.

Remove the foil carefully. Drizzle the remaining sauce over the fish and sprinkle the julienned scallions on top. Re-cover and steam for an additional 4-6 minutes.

Transfer the cooked fish to a serving platter. Serve hot over a bed of steamed jasmine rice. Optionally garnish with fresh cilantro.