Cajeta

In a large, heavy saucepan bring the goat's milk to simmer over medium heat. Add the sugar and stir until completely dissolved.

In a small bowl stir together the cow's milk and baking soda. Ladle in a small amount of the hot goat's milk, stirring constantly. Remove the pan from the heat and whisk the soda mixture into the hot goat's milk.

Return the pan to the stove, stir well with a wooden spoon, and continue to simmer over medium heat, stirring frequently unit the mixture begins to thicken, about 30 minutes. As the mixture darkens, return the heat to low and stir constantly unit the cajeta becomes a dark caramel color and coats the back of a spoon, another 20 minutes or so.

Pour the cajeta into a bowl and let cool, then stir in the vanilla.

Store any unused cajeta in the refrigerator.