1) Preheat the oven to 190 degrees C.
2) In a small bowl, mix the yoghurt, lemon juice, garlic and ginger.
3) Finely chop the mushrooms and onion and add to the yoghurt mix.
4) Put the haddock fillets into an ovenproof dish and season, then spoon the mixture over the top of each one.
5) Cover and bake for about 15-20 minutes. The fish is cooked when it flakes easily. Garnish with some fresh coriander and serve with steamed veg.