This is adapted from a food blog recipe I found. I eat lots of salmon and I am posting this here for safekeeping. I know these flavors are some of my favorites for salmon, and I think this would be good on the grill, or in the oven too.
Slice the onions into thin rings on a mandolin or carefully with a knife.
In a saucepan, heat the oil. Add the butter and garlic. Add the wine and cook the onions down until they are translucent.
Add the brown sugar, mustard and honey and stir until blended. Salt and Pepper to taste. Turn to low heat and simmer about 15 minutes.
Rinse and pat dry the salmon fillet and place it on a large piece of foil. Add salt and pepper the top to taste. Add about ½ of the onion mix to the top of the salmon and pour the ¼ cup of the liquid from the skillet around the fillet.
Seal in foil and cook on the grill over medium heat 15-20 minutes depending on the thickness of the fish.