Dulce De Leche

Directions

1. 1
   Place the milk in a large, heavy saucepan over medium-high heat.
2. 2
   Bring to a boil and allow skin to form on top.
3. 3
   Do not stir.
4. 4
   The skin will thicken and puff up.
5. 5
   Reduce heat to medium and remove the skin.
6. 6
   Increase heat to medium-high and repeat the process 3 times.
7. 7
   Add the sugar and vanilla bean, and stir until the sugar has melted, about 2 minutes.
8. 8
   Reduce heat to low and stir in the baking soda.
9. 9
   Simmer milk, stirring often, but taking care not to break the film of cooked milk forming, on the inside of the pan.
10. 10
    Simmer, skimming the foam (not skin) until reduced by half, about 1 hour.
11. 11
    Reduce the heat to very low and simmer for another 3 and 1/2 hours, stirring and skimming foam occasionally.
12. 12
    The mixture will brown as it cooks.
13. 13
    Strain the completely cooked mixture through a sieve into a bowl, cover and refrigerate.