Preheat oven to 300ºF and adjust rack to middle position. Line an 11 x 7-inch baking pan with parchment paper so the sides of paper overhang.
Place the almonds, cashews, coconut and seeds in a large mixing bowl. Heat oil, honey and salt in a small saucepan over medium heat. Bring to a simmer. Stir in the vanilla and pour mixture over nut mixture. Fold until incorporated. Pour mixture into the baking dish and press into the bottom of the pan. Bake for 30 minutes. Cool completely before cutting (this step is very important. If you cut while they are warm, they will fall apart). Holding onto the parchment, gently lift the bars out of the pan and place on a cutting board. Using a large knife, cut granola into bars. Keep in an airtight container for 10 days.
Dehydration Method:
If you took the time to soak and dehydrate the nuts and seeds then you might want to use this option to bake the bars – Follow instructions above and dehydrate at 170ºF (or as low as your oven will go) for about 7-8 hours, until the outer edges are just slightly golden brown. Cool completely before cutting.
A few tips:
To ensure the granola cuts into clean uniform bars, I usually start in the middle and cut with a large chefs knife. You can also put the granola bars in the refrigerator after baking for 30 minutes to ensure the honey (the glue that binds the bars together) hardens to make cutting easier (this step can be helpful if you live in a humid climate).