Here is my condensed milk recipe (it is decadent to say the least!):
Condensed Milk (for baking)

Add 2 tsp molasses and 1/4 tsp vanilla extract and 2 tsp extra butter (to make sure the dulce de leche topping sets up properly) - this results in a confection reminiscent of caramel, dulce de leche or a toffee-like flavor. When sufficiently cooled and thickened in refrigerator, use about 2/3 to 1 cup as a topping for a New-York style cheesecake, for instance. The carbs increase from 2.9 to 3.3 per serving. Using 2/3 cup, this adds less than 3 g of carbs per slice of cheesecake (12 servings). Freeze the rest if you have that kind of will power. Also, remember most cheesecakes freeze really well, sliced, in a sealed tupperware-type container.

Helpful Hints: For many low-carbers the molasses will be a total no-no. Instead flavor the condensed milk with butterscotch extract (no more than 1/2 tsp) or caramel extract (is there such a thing? - Caramel DaVinci Sugar Free Syrup would work but be careful to use no more than 1 or 2 tsp, otherwise the mixture will not be viscous enough for a topping.