If making you own dulce de leche, follow the instructions below:
Start with a can of condensed milk. Remove the sticker label and place the can in a pot large enough to completely cover the can with water.
Fill with water ensuring the can is fully submerged and turn the pan on medium high heat.
When the water comes to a boil, reduce the heat to medium/ medium-low to allow a simmer. Simmer for 2½-3 hours checking on the level of water every 30 mins and refilling as necessary to keep the can submerged. After 2 hours of simmering you will obtain a light golden dulce de leche; at 3 hours, you will have a darker, more flavourful dulce.