Preheat the oven to 190 C / Gas 5.

Slice onions into semicircles. Put onions in a frying pan with a drizzle of olive oil and fry gently until soft and brown, about 10 minutes. Season with marjoram or oregano and a little salt and set aside.

Cut the orange into slices and place them in a single layer in a clean frying pan, cooking them on high until lightly browned on both sides, about 3 minutes. Add lemon juice and drizzle of honey. Add the star anise and water, bring to the boil and remove from the heat.

In a baking tin large enough to fit the whole fillet, lay down sheets of aluminium foil with enough overlap to wrap the fillet up like a parcel. Add the onions in a layer and then place the salmon fillet (if you use the skin, place the skin side down), on top of the onions. Rub the fillet with salt and pepper. Lay the orange slices and star anise evenly spaced over the top of the fillet, and place 2 lemongrass which have already been cracked into each side.

Fold up the edges of the foil over the fillet to make a parcel, making sure to seal the edges well.

Bake the parcel for 35 to 40 minutes. Remove from the oven, open foil and serve.