Preheat oven to 180 degrees. Line a 9-inch square baking dish with parchment.
Combine 3 cups old-fashioned rolled oats, 1 cup crispy brown rice cereal and 1/4 teaspoon salt with 2 cups total of a ‘mixture’ of your choosing in a large bowl.
Then combine 2/3 cup brown rice syrup, 1/2 cup Nut or Seed Butter and 1 teaspoon ‘flavoring’ in a microwave-safe bowl. Microwave for 30 seconds (or heat in a saucepan over medium heat for 1 minute). Add to the dry ingredients and stir until evenly combined. Transfer to the prepared baking dish and firmly press into the baking dish with a spatula.
Whether you choose chewy or crunchy granola bars, both will be soft when they come out of the oven but will firm up as they cool.
For chewy granola bars: Bake until barely starting to color around the edges and still soft in the middle, 20 to 25 minutes.
For crunchy granola bars: Bake until golden brown around the edges and somewhat firm in the middle, 30 to 35 minutes.
Let cool in the dish for 10 minutes. Using the overhanging parchment, lift the bars out of the baking dish onto a cutting board (they will still be soft). Cut into 24 bars and let cool completely without separating the bars, about 30 minutes. Once cool, separate into bars.
To make ahead: Individually wrap and store at room temperature for up to 1 week.