Combine the butter, brown sugar, water, ground cinnamon, and kosher salt in a saucepan. Bring to a simmer of medium heat. Cook while stirring for 1-2 minutes, until the sugar is dissolved.
Stir in the vanilla and chopped pecans. Continue cooking for 2-3 minutes, stirring constantly.
Remove from heat and spread on a parchment-lined rimmed baking sheet to cool.
Video
Notes
Store cooled pecans at room temperature in an airtight container for 1-2 weeks, in the fridge for 2-3 weeks, or in the freezer for 1-2 months.