Preheat oven to 250 degrees. Place the pecans on ungreased shallow baking pans and heat for 10 minutes.
Take 1 tablespoon of butter and spread on the sides of a large saucepan. Add the sugar, salt, cinnamon and water.
Cook this mixture on low heat while stirring until the sugar is dissolved.
When the sugar has dissolved, continue cooking and stirring, now on medium heat until the mixture comes to a boil.
When it starts boiling, cover and cook for 2 more minutes.
Uncover and continue cooking (now without stirring) on medium heat until the mixture reaches a temperature of 236 degrees. You will need a candy thermometer for this step.
When it reaches 236 degrees, remove the mixture from the heat and add the vanilla. Next add the warmed pecans and stir to coat them with the mixture.
Use the remaining 2 tablespoons of butter to grease the pans.
Add the coated pecans and place trays back in the 250 degree oven for 30 minutes. Stir the pecans every 10 minutes.
When you take the pecans out of the oven the sugar should have started to crystallize. If it is still in a syrupy stage, just put them back in the oven for a few more minutes.
When done, place pecans on wax paper to cool. When cooled, place in a sealed container.