Preheat oven to 375°F (200°C).
Prepare 1 large piece of parchment paper per filet. Go large. The paper needs to be able to be folded over the fish and the vegetables and sealed shut.
Start with a layer of thinly sliced vegetables. I often use spinach first. Salt and pepper.
Place the filet on top. Salt and pepper the filet and sprinkle on olive oil.
Layer more vegetables and lemon slices onto the filet. Salt and pepper. More olive oil if it looks dry.
Fold the parchment paper around the fish and vegetables and crease the edges for an improvised seal.
Place the packets onto a baking sheet.
Bake for about 10 minutes. The baking time depends greatly on the thickness of the filets and the amount of vegetable you have packed them in. Don’t be shy about opening one of the sealed packets after 10 minutes to check if the fish is cooked.
Serve in the parchment packet for greatest effect.