Combine all the ingredients in large pot over medium low heat, stir until the sugar or panela is well dissolved. Reduce the heat to low.
Continue cooking until the mixture is significantly reduced and starts to thicken while the color changes from a creamy beige to a caramel tone – it will take between 2 ½ hours to 3 hours for the dulce de leche to be done.
During the first 1 ½ hours you will need to stir occasionally to prevent it from boiling over and sticking. During the last hour it needs to be stirred more frequently and has to be watched very closely to keep it from burning – you can also decrease the heat to low. Cook it until it has a dark amber or caramel tone and has a creamy consistency. Keep in mind that it will thicken more when it cools down.
Can be served warm or cold and must be kept refrigerated.
8 cups of whole milk
2 to 2 ½ cups sugar or panela/piloncillo raspadura, adjust based on the level of sweetness you prefer
1 teaspoon vanilla
¼ teaspoon baking soda