Preheat oven to 375 degrees. In a small bowl, combine sugars, salt, flour, & cinnamon. Set aside.
Put the apple slices in a bowl, add the lemon juice, and give it a stir. Add the dry mixture and stir to coat. Then add in the lemon zest and another quick stir. Set aside.
Roll out your pie crust. Lay rolled pie crust dough onto a bar pan or cookie sheet with an edge, lined with parchment paper.
Pile your apples in the center. Simply begin folding the edges of the dough over the apples, gently pressing them into place. Dot the apples with the butter pieces.
Bake the galette for 35-45 minutes, or until golden and bubbly.
Allow it to rest and cool for 10 minutes or more before serving. The inside will ooze when you cut it, that’s normal. Serve with ice cream or whipped cream.