Thinly slice the apples to about 1/16 inch (1.5 mm) using a mandolin slicer or a sharp knife.
If you prefer, you can leave the skin on the apples.
In a large bowl, gently toss the apple slices with EVOO until each slice is lightly coated.
If you prefer sweet and spiced chips, combine the sugar and cinnamon in a separate bowl, and sprinkle over the apple slices, tossing to coat evenly.
Arrange the apple slices in a single layer on baking sheets lined with parchment paper, ensuring no overlap.
Place the baking sheets in the preheated oven and bake for 1 to 2 hours, or until the apple slices are crispy and golden brown, flipping the slices every 30 minutes to ensure even baking.
The exact baking time can vary depending on the thickness of the slices and oven temperatures, so start checking around the 1-hour mark.
Once the apple slices have achieved a crisp texture, remove them from the oven and let them cool on the baking sheets for about 10 minutes; they will continue to crisp up as they cool.
Serve the apple chips as a healthy snack, or use them as a crunchy topping for salads or oatmeal.
Store any leftovers in an airtight container at room temperature for up to a week.
