Preheat oven to 425º F. Line rimmed baking sheet with parchment paper or aluminum foil for easiest cleanup.
Place salmon, skin side down, onto lined baking sheet. Sprinkle brown sugar on top of salmon, making sure entire flesh side of salmon has a light dusting. Sprinkle garlic salt onto the salmon. Bake salmon until it has cooked through, about 12-15 minutes.
Remove from oven and top the salmon with optional garnishes, if desired.