Preheat oven to 350°F and line a rimmed half baking sheet with parchment paper.
Spread the oats and chopped almonds in an even layer on the prepared baking sheet and bake until light brown and smelling toasty, stirring regularly, about 10-15 minutes.
Line an 8” x 8” baking pan with parchment paper.
While the oats and almonds are toasting, combine the honey, brown sugar, and butter in a heavy-bottomed medium saucepan over medium heat and stir until melted. Stir in salt, cinnamon, and vanilla, then fold in the toasted oats mixture and ground flaxseed until evenly distributed.
Scrape into prepared baking pan and spread out. Use a piece of parchment paper to press down and level out the mixture to the edges.
Cover with plastic wrap and chill in the fridge for at least 2 hours. Once solid, lift from the pan using the parchment paper, and use a very sharp knife to cut into 12 granola bars.
Video
Notes
Storage: Store the homemade granola bars in an airtight container. They can be kept in the fridge or at room temperature for up to 7 days.