Preheat the oven at 150°C and line two baking sheets with foil.
Cut 2 apples into 2-mm-thick-slices and place them onto the lined sheets. Bake until dry, turning each slice upside-down every 15 minutes. Cool and set aside.
Puree the remaining two apples (peeled and cored) with a blender.
In a medium bowl mix oats, pureed apples, cinnamon and honey. Spread this mixture onto a foil-lined baking sheet.
Bake for one hour (or until your granola is golden and crisp), stirring it every 15 minutes.