In a small pot, combine the water and sugar and bring to a gentle boil over medium heat. Set aside to cool.
Place the apples on a flat surface. Using a mandoline or sharp knife, cut each one, placing the core end of the apple in front of the blade, into rounds as thin as you can manage. Remove any seeds as you cut and sprinkle them with lemon juice. Submerge the apple slices in the syrup and allow them to "rest" for a few hours or, even better, overnight.
Preheat the oven to 200 degrees F.
Remove some of the apples from the syrup and lightly dry them on a kitchen towel. Place them in a single layer on a baking sheet with parchment or on a tray fitted with a baking rack. Note: you may want to place something heavy, like a metal spoon, at each end of the paper to prevent the paper from folding over as the chips bake. Bake in the oven until crispy, about 1 hour.
Recipe courtesy of Alex Guarnaschelli