All ingredients ready? Let's begin!
Preheat your oven to 300°F. Line a rimmed baking sheet with parchment paper. Alternatively, spray the sheet pan with non-stick vegetable oil.
In a large mixing bowl, whisk the egg whites vigorously until just frothy, approximately 15 to 30 seconds.
Whisk in the brown sugar, vanilla, cinnamon, and kosher salt.
Add the pecans to the bowl and mix well until all are evenly coated with the egg white and sugar mixture.
Pour the coated nuts and any excess liquid onto the prepared pan. Spread them out into a single layer.
Place the pan in the oven and bake for 15 minutes. Flip the nuts with a spatula and spread them out into a single layer again. Return the pan to the oven and bake for an additional 15 minutes.
Remove the pan from the oven and allow the nuts to cool completely. They should continue to crisp up while cooling in the pan.
Serve the nuts at room temperature or store them in jars with lids for up to 7 days.