Place the whole milk, heavy cream, sugar and salt in a large pot, like a dutch oven. The larger the surface area, the quicker your milk will condense.
Stir the miixture to incorporate all the ingredients and bring the mixture to a simmer. Bubbles should be breaking te surface.
Let the mixture simmer for about 30 minutes. The time may vary depending on the weight of the pot you use and the temperature of your stove
Occassionally stir the mixture using a rubber spatula, scrapping the bottom and sides of the pot.
After about 30 minutes, the mixture will start to foam and bubble rapidly. This means that you are getting close. Make sure to to keep stirring, at this point. The mixture should have thickened and be a very light tan color.
To check to see if you have condensed the mixture enough you can pour it into a measuring cup. You should have between 1-1 1/4 cups.
Once done, strain the condensed milk through a strainer to catch any lumps or bits.
Stir in the vanilla.
Place in a jar, cover and place in the fridge. Let it chill at least 6 hours before using. It will keep about a week in your fridge.
