Heat a large frying pan or skillet pan on medium heat. When hot, add the sugar, water, vanilla extract, salt and cinnamon, if using it, and mix until fully combined. Allow to heat up, stirring occasionally.
When the sugar has completely dissolved, add the raw, unsalted pecans. Watch over the pan and continue stirring often until most of the sugar mixture has been coated and beginning to crystallize.
Remove pan from the heat and allow to sit for 1-2 minutes, before using a wooden spoon to stir almonds together to avoid immediate, overlarge clusters forming. Allow to cool completely before breaking up properly.
Preheat oven to 250 degrees. Line a large baking tray with parchment paper and set aside.
Follow directions as above then spread out pecan halves on a single flat layer. Bake for 45 minutes, stirring occasionally. Once pecans have just begun to crystallize, remove and allow to cool for 1-2 minutes, before stirring once again to avoid immediate overlarge clusters forming. Allow to cool completely, before coating in an extra tablespoon or two of sugar.
TO STORE: Candied pecans can be stored at room temperature, in a sealed container, for up to 4 weeks. You can refrigerate them if you'd like them to keep longer. TO FREEZE: Place pecans in a ziplock bag and store in the freezer for up to 6 months.