Prep the pan and oven. Heat the oven to 300°F (150°C).
Line a large baking sheet with parchment paper for easy cleanup.
Mix the sugar coating. In a small bowl, whisk together brown sugar, granulated sugar (if using), cinnamon, and salt. Break up any sugar clumps.
Whisk the binder. In a large bowl, whisk the egg white until frothy, 20–30 seconds. Stir in vanilla and oil or melted butter, if using.
Coat the pecans. Add pecans to the egg white mixture and toss until every piece looks glossy and wet.
Add the sugar blend. Sprinkle the sugar-cinnamon mixture over the pecans.
Toss well so the coating sticks evenly.
Spread and roast. Pour pecans onto the prepared sheet and spread into a single layer. Bake for 22–28 minutes, stirring once halfway. They’re done when fragrant, slightly darkened, and dry to the touch.
Cool for crunch. Let pecans cool completely on the pan.
The coating will firm up as they cool, giving that perfect candy-like crunch.
Taste and finish. If you like a sweet-salty hit, sprinkle a pinch of extra salt while they’re still warm. Break apart any clusters once cooled.