I love reducing my single-use waste as much as the next millennial, but I say use the parchment paper. Unlike plastic, it's compostable and will keep your fudge from sticking to the pan better than butter or (worse for the planet) non-stick sprays. You can lift the entire batch of fudge out of the pan at once for easy cutting and reuse the same sheet between layers of fudge while storing in your reusable airtight containers. I call that a win-win.