Turn on the oven to 300 degrees. On a rimmed baking sheet lined with parchment paper, spread out the oats, nuts, pumpkin seeds and amaranth. Bake, stirring halfway through, until the nuts are just beginning to color and the oats are crispy, about 20 minutes. Scrape it all to a large bowl, sprinkle on the flour and toss to coat. In a medium bowl, whisk together the oil, honey, sugar and salt. Pour this mixture over the oats and mix until everything is evenly coated. Spread the mixture into an even layer on that same parchment-lined baking sheet and return it to the oven. Bake, stirring every ten minutes, until the oats are a rich caramel color, the nuts are browned and shiny, and the granola is fragrant, about 40 minutes. (The baked mixture may still feel dampish when you stir it with a spatula, but it will crisp as it cools.) Transfer the baking sheet to a cooling rack and let the granola cool completely. With your hands, break the granola into bite-size clusters and transfer it to an airtight container; it will keep for two weeks or so.