In a medium to large bowl, whisk together egg white and balsamic vinegar until frothy.
Two: Prepare Coating:
Add brown sugar, cinnamon, and salt to egg white mixture and stir to combine.
Three: Add Nuts & Bake:
Add pecan halves to coating mixture and stir or toss with your hands until all nuts are completely covered. Turn nuts onto a Silpat or parchment-lined baking sheet and spread apart in a single layer. Bake in a pre-heated 300° oven for 40-50 minutes until slightly toasted in color. Let rest at room temperature for 5-10 minutes before removing from pan.