Haddock Quiche

• 300 grams smoked haddock
• 150 grams swiss cheese (grated)
• 4 eggs
• 1 quiche crust
• 1 onion (chopped)
• 1 salt and pepper
• 350 ml cream
• 45 gr mushrooms (sliced)
• 28 gr butter
• 22 gr green onions (finely sliced)