In a small saucepan, combine maple syrup, ginger root, 3 tbsps of the lemon juice, all of the soy, garlic, salt and pepper and simmers until liquid reduces to one cup. If making immediately pour half of the liquid into a small container and set aside, add remaining tablespoon lemon to remaining half in pan and keep warm while you prepare fish. (Sauce can be made 2 days ahead of time)

Preheat oven to 350F.

Lightly oil cedar plank and heat in the middle of the oven for 15 minutes. If you're not using a cedar plank, lightly oil a shallow baking pan large enough to hold trout pieces.

Arrange green onions in one long layer on plank or in pan to create a bed for the trout.

Place trout, skin side down, on green onions and brush with glaze you set aside.

Roast in the middle of the oven until just cooked through. About 35 minutes if using a cedar plank and 20 if using a baking sheet. Remove from oven and cut into 6 pieces. Drizzle fish with remaining sauce once plated.