Place a large non-stick skillet over medium heat. Add the butter and allow it to melt completely until lightly bubbling but not browned.

Add granulated sugar, brown sugar, cinnamon, and salt to the melted butter. Stir continuously until the sugars dissolve and the mixture becomes smooth and syrupy. Keep the heat at medium to avoid burning.

Add the pecan halves to the skillet. Stir constantly so every pecan is evenly coated with the sugar mixture. Continue cooking for several minutes until the syrup thickens and clings tightly to the nuts.

Remove the skillet from heat and immediately stir in the vanilla extract. Mix quickly to distribute the vanilla evenly before the coating begins to set.

Spread the candied pecans in a single layer on parchment paper or a silicone mat. Separate them slightly and allow them to cool completely. As they cool, the sugar coating will harden and become crunchy.