Remove the paper label from the can of condensed milk.

Place the unopened can in a large pot and cover it with water (at least 2 inches above the top of the can).

Bring the water to a boil, then reduce the heat to a gentle simmer.

Let the can simmer for 2 to 3 hours (2 hours = lighter and creamier, 3 hours = rich and caramelized). Always keep the can submerged in water — add more hot water if needed.

Use tongs to carefully remove the can from the pot. Allow it to cool completely before opening.

Open, stir, and enjoy.