The French call it, en papillote – a technique of baking food encased in parchment paper. Unlike parchment paper used for writing (which is not actually made from paper), parchment paper sold for kitchen use is treated with sulfuric acid. The process creates a surface that is sleek, smooth and impervious to oil and moisture. It is also resistant to heat up to 425°F, according to PaperChef.com, a manufacturer of parchment products. In the final process, a silicone coating is added that creates a further non-stick surface.