In a mixing bowl whisk together maple syrup, soy sauce and garlic. Place salmon into a baking dish then pour maple syrup mixture evenly over salmon. Cover and refrigerate 30 minutes, carefully rotating salmon once halfway through. Preheat oven to 400 degrees during last 10 minutes of marinating salmon.

Spray a 13 by 9 inch baking dish with cooking spray then transfer marinated salmon into greased dish (don't discard marinade). Bake in preheated oven until salmon is cooked through, about 15 minutes.

Meanwhile, pour marinade into a small saucepan, bring to a boil over medium-high heat, stirring frequently. Once it reaches a boil, reduce heat slightly and allow to cook several minutes, stirring frequently, until reduced to 1/4 cup.

Serve salmon warm with 1 Tbsp of the maple soy glaze drizzled over top and black pepper and green onions if desired (I don't think it needed salt because of the soy but feel free to add it if you think it needs it).