I saw a gorgeous fillet of salmon on the fishmonger's slab and knew right away that I wanted to eat it with the Yukon Gold potatoes and the almost needle fine beans I'd bought the day before. Cooking food sealed in parchment paper is a classical French method known as "en papillote". I love, love, love this way of preparing fish as it's almost laser quick, mess free, healthy and relies very little on fat for flavour.

What you get is a cut of fish cooked to absolute perfection, which for me,...