Place can in a large pot and fill the pot with water so the cans are submerged.
Place the pot over medium high heat. As soon as the water comes to a boil reduce to a simmer then just keep an occasional eye on the water level and refill with hot water as necessary.
3 hours of simmering will give you a perfect Dulce de Leche.
Let cool the can than open it. Enjoy the perfectly sweet, creamy Dulce de Leche.
Notes
You can simmer more cans if you'd like more dulce de leche, you're just limited by the space In your pot.