Instructions:
1. In a heavy bottom saucepan, add the milk and sugar, then bring to a boil on a high flame.
2. Stir frequently and cook for about 10 minutes. Turn the heat down to low, then add the baking soda. There should be bubbles forming in the mixture.
3. Cook on low for 30 minutes, or until the mixture thickens slightly and the color changes to a pale yellow.
4. Allow to cool completely before using. The mixture will thicken more while it’s cooling.