Cut 2 slits in each fillet, about 3 cm long and 3/5 of the thickness of the fillets, fill each with a tsp of butter. S+p, place in a single layer in a frying pan ( with lid ! ), pour water, cover and steam over medium heat for 6-8 min.
Meanwhile, stir through onion, balsamic vinegar, mint, s+p, stand 5 min. Later, toss in the oil.
Place each fillet on a plate, drizzle with cooking liquid and pour 2 tbsp of the salad dressing over each.
Note Super quick, takes less than 20 min Mint and the buttery fish go great together. Served with couscous.
Ralph.