Remove the label from the can of condensed milk. It is no longer needed! If you leave it on, you'll get a papery mess in the water.

Place the can in a small pot and fill it with enough water to come up to one inch (2.5cm) from the top of the can. You will need to add more water during the cooking process to make sure water doesn't go below this level as it evaporates. Don't let the water come higher than 1/2 inch (1.25cm) from the top of can, though, as you don't want any getting on the top of the can and going into the holes you pierced.

To prevent the can from rattling in the water (which can be annoying when you consider that it'll need to be in there for several hours) put a rag under the can.

Place the pot on your stove and turn it on to medium-high heat.

Watch the water closely until you see the water come to a simmer.

Lower the heat to hold the water at a simmer. A soft Dulce de leche takes about 2 1/2 hours.

Remove the can with tongs or an oven mitt and place on a rack to cool. Be careful when emptying the contents, as you can get burned.

Open the can carefully with a can opener and pour into a bowl. The top will be more fluid, and there will be thicker, darker chunks at the bottom which will need to be scraped out. When everything is in the bowl, whisk together to make it homogeneous.