Place all the ingredients for soaking into a large bowl. Stir to thoroughly combine. Then cover and let sit at room temperature for 24-30 hours.
After 24 hours, preheat the oven to 200F and line 2 baking sheets with parchment paper. Mix the maple syrup, salt, cinnamon, and vanilla into the soaked oat mixture, until evenly combined. Pour half of the granola mixture onto each baking sheet. Spread into a thin, even layer.
Bake the granola at 200F for 8-10 hours, until very dry and crispy. To insure crispy granola, flip and mix the granola around on each sheet tray every 2 hours. After the granola has dehydrated, I like to turn the oven off and leave it in the warm oven overnight.
Serve with almond milk, over fruit/yogurt, or eat it by the handful! Enjoy!