Position racks in the upper and lower third of the oven; preheat to 200 degrees F. Line 2 large baking sheets with parchment paper.Advertisement
Combine water and lemon juice in a medium bowl. (The lemon juice helps prevent browning.)
Using a sharp knife or a mandoline (if you have one), slice 2 large apples as thin as possible, about 1/8 inch thick. (We skip peeling and coring because we like the look of the dried skins and the pretty pattern the core makes in the center.) Soak the slices in the lemon water for 30 minutes. Drain and pat the slices as dry as possible with paper towels (or clean kitchen towels). Place on the prepared baking sheets in a single layer.
Bake the slices on the upper and lower racks for 1 hour. Remove from the oven and turn each slice over; return the pans to the oven. Bake 1 more hour for soft dried apples or about 2 more hours for crispy apple chips. (Timing depends on your oven, the type of apple and thickness of the slices; check periodically and reduce or increase the total time as needed.) Turn off the oven, crack the door and leave the apples in the oven until the oven cools completely, 1 to 2 hours.
Make Ahead Tip: Store airtight for up to 1 week or refrigerate for up to 1 month.