Preheat oven to to 200 C / Gas 6 and prepare baking tray with foil.
Place saucepan on a low heat, add olive oil, white wine, honey, balsamic vinegar, mustard, black pepper and salt, then add garlic and onion. Leave to simmer until onions and garlic have softened, usually around 3-4 minutes.
Place salmon fillets on the baking tray and coat in the sauce just made, ensuring the sauce is all over the fish. Then cover lightly (not airtight) with foil. This will save the fish from drying out.
Place the foil covered tray into the preheated oven for 13 minutes, or until the fish flakes when placing a fork slightly into the corner of the fish.
Once removed from the oven and placed on plate make sure you tip the excess sauce from the baking tray over the fish.
Serve on a bed of baby leaf salad with new potatoes and cherry tomatoes on the vine, Can be topped with onion shavings for presentation.