½ teaspoon baking soda dissolved in 1 Tablespoon water
Method
In a medium to large pot/ dutch oven/cazo, combine the milk, sugar and cinnamon and set over medium heat. Stir regularly until the milk comes to a simmer. All of the sugar should have dissolved by now. Remove the pot and stir in the dissolved baking soda. It should foam up. Return to heat.
Adjust the heat to maintain the mixture at a brisk simmer. Cook, stirring every now and then, until the mixture is a golden. At this point, stir frequently for a few minutes as the mixture changes to a deeper caramel color and a thicker consistency.
Strain if necessary. Store in a jar!
Recipe by Gouramanda at https://gouramanda.com/pound-cake-with-cajeta/