Make the applesauce: Peel and core the first 1 lb of apples, then cut them into 1-inch pieces. I like to use a melon baller to remove the core (mine is from Pampered Chef), and a serrated peeler for peeling the apples. Zest a lemon with a microplane grater, then juice it and set the juice aside for later.
Bring the apples, water, 1/2 cup sugar, zest, cinnamon, and boiled apple cider to a boil in a 2-quart heavy saucepan, stirring occasionally, then reduce heat and simmer, covered, 15 minutes. Remove the lid and simmer until most of liquid is evaporated, about 5 to 10 minutes more. Mash the apples with a potato masher or a fork to a coarse sauce (if you need to...mine kind of fell apart on its own), then set aside to cool while you prepare the sliced apples.
Preheat the oven to 400°F. Line a half sheet baking pan with Silpat or parchment paper.
Prepare the apple slices: Peel and core the other 1 lb of apples, then cut into 1/8-inch-thick slices. Toss the slices with the lemon juice and 1/3 cup granulated sugar.
Assembly: Unfold the phyllo dough, then quickly cover with a sheet of plastic wrap and a lightly dampened clean kitchen towel to prevent it from drying out.
Place one sheet of phyllo lengthwise on the prepared baking pan and brush with the ghee. Place a second sheet of phyllo on top crosswise, then brush that sheet lightly with the ghee. Repeat until all 8 sheets are used.
Spread the cooled applesauce in center of the phyllo stack, leaving a 2-inch border, then top sauce with the sliced apples in a nice pattern, mounding slightly. Dot with the butter.
Turn the corners of the phyllo over to form an octagon. Press flat. Fold the pastry edge over the filling to form a rim, pleating the dough as necessary. Brush the top of the pastry rim with a last bit of ghee, then sprinkle the crust and filling with sugar.
Bake the galette in middle of oven until the pastry is golden and the apples are tender, about 20-22 minutes. Remove from oven.
Melt the apple jelly in the microwave on HIGH for 20-30 seconds, then gently brush on the galette (you don’t want to break the phyllo crust). Allow the galette to cool on the Silpat until room temperature.
Once cooled, cut with a pizza cutter or a sharp knife. Enjoy!