There are a few easy ways to ensure a fully cooked galette crust: Bake your galette on a parchment paper-lined heavy bottomed baking sheet. Use a baking stone if you have one. Be sure to use arrowroot starch in the filling. Most importantly, be sure to cook the galette long enough (and tent with foil if the top starts to brown too quickly). You’ll know when it’s done when the crust is golden and the peach juices begin to bubble.