Preheat oven to 300° F, and line a large rimmed baking tray with parchment paper.
Place oats and chia seeds in a mixing bowl and set aside. If omitting chia seeds, see note below.
In a microwavable bowl, heat the peanut butter and honey until melted, stirring after 20-second intervals. Stir in the vanilla and salt until the mixture is smooth. Pour the honey and peanut butter mixture over the oats, and stir until all oats are evenly coated.
Spread the oat mixture evenly in clumps on the prepared pan and bake for about 20 minutes or until golden brown. Rotate the pan halfway through baking. Be very careful not to overbake.
Granola becomes crunchy as it cools. Once completely cooled, store in an airtight container.
Notes
If omitting the chia seeds, add an extra ¼ cup old-fashioned oats.