Measure the sugar into a large sauce pot.
Add the whole milk.
Measure the baking soda into a small mixing bowl.
Add the water and stir to dissolve.
Bring the milk and sugar to a simmer.
Remove from the heat and stir in the baking soda mixture.
The milk will immediately foam up. Let the foaming settle for a minute and then return the pot to medium heat.
Scrape the seeds from the vanilla bean and stir them into the milk.
Once the milk comes back to a simmer transfer it into a hotel pan. You could also add a cinnamon stick or star anise at this point if you would like.
Place the hotel pan in the Cook & Hold pre-heated to 325F. Cook for 5 hours at 325F and hold at 200F overnight 8-12 hours.
A thin skin will develop on top during the cooking process. Peel back the corner and strain the liquid through a fine mesh strainer.
Fill mason jars with the dulce de leche and keep refrigerated.