Prepare 2 pieces of aluminium foil large enough to wrap the each salmon piece. Slice the onion into about 1cm rounds and put two of them on each piece foil.

Put a piece of salmon on the onions. Pour in a tsp sake or white wine.

Then put chopped mushrooms and sweet snap on the fish.

Add a tsp of lemon juice, season with salt and pepper.

Wrap the foil around the fish to avoid water coming in when cooking.

Pour water into a pan about 2 cm deep and then put in the wrapped salmon. With the lid on, boil/steam for about 15 min on a medium heat.