Put the condensed milk in an aluminum pot (enamel, it will burn).
Put the saucepan on the stove and turn the burner to medium heat. While cooking, periodically stir with a wooden spatula.
As soon as the milk starts to thicken, reduce heat to the minimum.
Then be guided by your own taste preferences. The longer you boil the condensed milk, the thicker and darker it becomes. But most importantly, don't forget to stir it, otherwise it will burn.
Cooking can be and in a microwave oven. To do this, put the condensed milk in a crock pot, cover with a lid. Put in oven and turn on medium heat. Set the timer for 40 minutes, at the expiration time check if the condensed milk will seem liquid, put be done to a turn.
There is also a way to cook the condensed milk in the microwave. You may not believe it, but this is the fastest way. As a microwave it is impossible to put anything iron, You will have to open a jar with condensed milk and pour its contents into a deep bowl. Set the microwave to medium and put the condensed milk boil for 15 minutes. Every 1-2 minutes it is necessary to get a bowl with condensed milk and stir it.
For starters, the condensed milk must be poured into a deep bowl designed for microwave ovens. Put the bowl with the condensed milk and mikrovolnovku, and cook it, putting the average power mode.