In a bowl, whisk together olive oil, brown sugar, soy sauce, Dijon mustard, lemon juice, and garlic powder to create the marinade.
Place salmon fillets in a shallow dish or zip-top bag and pour the marinade over them. Marinate in the refrigerator for at least 30 minutes.
Preheat the grill to medium-high heat (about 375°F).
Grill salmon skin-side down for 6-8 minutes per side until cooked through and slightly charred.
Check doneness by flaking with a fork; it should be opaque and easily flake apart.
Serve with any leftover boiled marinade drizzled on top alongside fresh veggies or salad.
