Pour the milk in a thick-bottomed stainless steel pot; when it is boiled, add sour cream, sugar, salt, baking soda and vanilla bean. Put everything on a slow fire for about 2.5-3 hours, stirring occasionally.In about an hour, the colour will change, you continue stirring until it becomes golden.
Leave boiling on a slow fire until it starts to thicken.When it is ready, pour it into a jar (about 800 ml) and let it cool.
Keep it in the refrigerator. It is recommended consuming during a month.
Jam has a nice taste, like a creamy caramel.