Preheat oven to 325 degrees. Spray two baking sheets that have rims (so the granola won’t fall off while cooking).
Mix the first five ingredients together in a large bowl and stir well. Add nuts and seeds. Add oil, and toss thoroughly to coat as much of the oats and nuts as possible. Add the vanilla to the agave or honey, and mix well. Pour the agave over the oats and nuts and stir with a spoon to mix well, so that everything is coated with the agave mixture.
Turn granola onto prepared baking sheets and bake for 20 minutes at 325 degrees. Turn oven temperature down to 180 degrees and continue to bake for approximately 45 minutes to one hour longer, until granola is slightly browned and crunchy.
Remove from oven and cool completely on the baking sheet before transferring to airtight containers. You will find that you need to break up large pieces of granola as you transfer it. Store with other cereals.