Preheat oven to 325. Line a large baking sheet with foil and spray foil with cooking spray.
Combine dry ingredients in a large bowl and stir until combined.
In another bowl, mix wet ingredients until smooth. Pour wet into dry ingredients. Stir until all the oats are coated.
Spread in a thin layer over the baking sheet. Bake for 30 minutes. Pull pan out of oven and stir oats. Smooth back out into a thin layer and sprinkle on walnuts. Spray whole pan with a light coating of non-stick spray. Return to oven for 15 more minutes.
Remove pan from oven and stir granola again and sprinkle on raisins. Set on a cooling rack. Once cool, store in an airtight container or bag.