Cut out 4 pieces of parchment paper of approximately 15 x 20 inches.
In the center of each piece of paper, lay down in this order 1 cup of baby spinach, 1 piece of cod fish, a pinch of salt, 1/2 cup leeks, 1 TBSP parsley, 1/2 TSP garlic, 1 TSP of olive oil, and another pinch of salt.
Gather up all sides of the parchment paper to form a package with the food inside. Tie a piece of kitchen twine around the neck of the package, as low as you can. Trim the excess of paper to 1 inch over the twine.
Place in the oven on the middle rack (or lower) making sure the parchment paper doesn't touch the heating element of the oven.
Bake for 30 minutes.
Remove the papillotes from the oven and place directly on a dinner plate. Open at the table and consume with a drizzle of lemon juice.
Bon appétit!
Recipe by A Squirrel in the Kitchen at https://asquirrelinthekitchen.com/aip-paleo-oven-baked-cod-fish-en-papillote-with-spinach-and-leeks/