Recipe Instructions:
1 quart whole milk
1 cup sugar
1/2 teaspoon kosher salt
1 vanilla bean, split
1/4 teaspoon baking soda
Mix the first four ingredients together in a saucepan over medium heat until the sugar dissolves. Take off the heat.
Stir in the baking soda, then put the mixture back on the stove over low heat. You want the mixture to bubble along the edges, but not to boil over.
Let the mixture cook for 1 1/2 - 2 hours, stirring occasionally. The color will begin to sneak from white to tan after an hour or so, then will darken rapidly. Keep a close eye on it now, stirring constantly. As the mixture darkens it will become thicker, and also nuttier. After your dulce de leche reaches your desired tone of caramel color, take it off the heat and let it cool slightly
If you want your dulce de leche to have a silky smooth texture, push it through a fine mesh strainer. If you don't want to go through the extra effort, it will be more than fine as is.
Dulce de leche keeps, refrigerated, for up to four weeks. Eat it over ice cream, spread on toast, or right out of the jar.