In a measuring cup with a spout or mixing bowl, whisk together the oil, soy sauce, honey, Dijon, garlic powder, and black pepper.
Pour over the top of the fish.
Seal the bag, removing as much excess air as you can, then set in a dish or on a plate to catch any possible drips. Let marinate at room temperature for 30 minutes or refrigerate for up to 1 hour (after 1 hour, fish tends to get mushy when marinated but if you MUST, you can refrigerate for up to 4 hours).
Cook the salmon, using your preferred method. OVEN: Line a 9x13-inch baking dish with parchment paper and place the salmon in the center (if using fillets, make sure they do not touch). Bake at 400°F for 11 to 14 minutes for 6-ounce fillets or 15 to 18 minutes for a single side, until the salmon registers 135°F on an instant read thermometer inserted at the thickest part of the salmon (the FDA recommends 145°F; I prefer to remove the salmon and let it rest so that it doesn’t taste dry). Remove from the oven and let rest 5 minutes.
GRILL: Place the salmon skin-side down on a HOT grill. Let cook without disturbing until the salmon releases easily with a spatula, about 6 to 7 minutes. Flip and cook on the flesh side, about 2 to 4 minutes more depending upon your grill temperature. Remove to a plate and let rest 5 minutes.
Notes
TO STORE: Refrigerate leftovers in an airtight storage container for up to 2 days.
TO REHEAT: Very gently rewarm salmon in a skillet on the stovetop over medium-low heat or in the microwave.
TO FREEZE: Freeze salmon in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.