Season trout fillets with salt and pepper. Place in a buttered baking dish. Melt butter in a small fry pan; add spring onions and sauté for 2 minutes; add garlic and ginger and sauté for an additional minute. Remove from heat; add tarragon, cayenne pepper, lemon juice, Worsecestershire sauce and Cajun pepper. Stir well and spoon over trout fillets.
Place under griller (7 to 10 inches from heat source) and cook for 10 to 15 minutes or until trout is done. The trout is cooked when it flakes easily when tested with a fork.
Serve with lemon or lime wedges along with a green salad and crusty bread.