Heat the oven to 220C (200C fan)/425F/gas mark 7.
In a roasting tray that will hold the fish fillets snugly, whisk half of the sesame oil with the soy sauce, gochujang, garlic, ginger and caster sugar.
Season the salmon with salt and lots of white pepper, then nestle skin side up into the soy mixture.
Dot with the butter, then roast for 10 minutes.
Toss the bean sprouts with the remaining sesame oil, then scatter them over the fish.
Return the tray to the oven for another five minutes, or until the fish is perfectly cooked.
Serve the salmon and its dressing over sticky rice, topped with the roast bean sprouts, chopped peanuts and a scattering of coriander.
