Why bake covered with foil for a short period? Vegan cheese tends to dry out and bake looking like shreds vs melting like dairy cheese. A trick is to cover your dish for part of the baking time which steams the cheese into melting rather than drying it out at the high heat. Do you need to do the foil part? No. But if you do you'll need to remove it after that 15 minutes because your Mac and Cheese dish needs to bake uncovered to allow excess moisture to be released. You want ooey and gooey rather than soup.