Fillet and skin the monkfish tail. Remove all of the dark-coloured meat and discard. Cut each fillet into squares roughly
Combine the red wine and fish stock in an ovenproof pan, add the cubes of monkfish and season. Heat the pan until the liquid just starts to tremble, then place it in the oven until cooked – this will only take about 5 minutes. When the fish is cooked, remove it from the pan, cover and keep warm.
Reduce the liquid over a high heat until only a quarter of its original volume remains. Add the veal stock, bring back to the boil, then add the spring onions and mushrooms. Continue boiling until the onions are cooked and the sauce has reduced slightly and thickened a little. The onions should remain a bit crisp. If they have cooked before the sauce has thickened, remove them from the pan – they can always be added later.