Preheat oven to 325 degrees. Mix flakes and oats in a medium bowl. Spread mixture on a rimmed baking sheet, and bake, stirring every 10 minutes, until light gold, 35 to 40 minutes.
Transfer to a large bowl, add the remaining ingredients, and toss to coat. Return to sheet, and spread in an even layer. Bake, stirring halfway through, until golden brown, for 20 minutes. Let cool. Granola can be stored for up to 3 weeks.