Start by peeling an apple and slicing it very thinly on a mandoline.
To prevent browning, you can hold the slices in a bowl of water and lemon juice, or rub the exposed areas with a cut lemon.
Meanwhile, bring a shallow pan of slightly diluted simple syrup (I used 2 cups water and 3/4 cup white sugar) to a light boil on the stove.
Slide the slices one-by-one into the lightly boiling syrup.
Cook for about a minute until the apple slices start to become translucent. Do not overcook. Remove with a slotted spoon, and pat each dry with a clean towel.
*Cook's note: Feel free to use a flavored or infused simple syrup (a one-to-one water to sugar heated until dissolved) such as ginger, lemon or orange.
Sprinkle with any seasonings you like,
such as ground cinnamon, allspice, ground ginger or coriander. (I went the purist route and left mine naked.)
Bake at 220°F for 45 minutes or until desired doneness, rotating the baking sheet halfway through. Since the apple chips won't fully crispy until they've cooled, remove one from the oven to test for crunch.
Remove and let cool on parchment paper or foil.
Once chips are fully cooled and crispy, store in an air-tight plastic at room temp after they cool. Re-heat in the toaster oven before eating if desired.