Preheat your oven to 400 degrees F.

Lay the fish out flat onto a piece of parchment paper. Make sure the parchment paper is big enough to wrap the fish up like a present. You can wrap each piece of fish in parchment, or a couple of pieces per package.

Generously season with salt and fresh ground pepper.

Slice the lemon and lay the slices on top of the fish.

Add butter.

Wrap up the fish: Fold the parchment paper up and around the pieces of fish, rolling the ends to seal.

Place the packets on a baking sheet.

Bake for 15-20 minutes, depending on the thickness of your fish. When the fish is opaque all throughout, it is done.