Pre-heat the oven to 350ºF.

Open the can of sweetened condensed milk. Pour the contents in a loaf pan or any smaller baking pan.

Place the loaf pan inside a larger baking pan.

Fill the baking pan with hot water until it is at the same level as the sweetened condensed milk, or higher, to form a water bath to prevent scorching.

Cover the loaf pan with foil.

Place in the pre-heated oven.

Bake for the minimum of 2 and a half hours, up to 4 hours. The longer you bake, the thicker and darker it will be.

Stir a few times during baking. Also, make sure to replenish the water from the water bath as it evaporates.

Let it cool down completely before consuming and serving.

Remove the label of the can. Keep the can sealed.

Inspect the can to ensure it doesn’t have any dents.

Place the sealed can in large pot, filled up with water, making sure the can is covered by a few inches at least.

Bring to a boil, reduce the heat, and let the water simmer for 2.5 hours to 4 hours.

Check on it constantly to make sure the water level isn't below the can, and that the can is submerged several inches.

After the desired cooking time, turn the heat off. For a lighter, more runny dulce de leche, cook for 2.5 hours, for a dulce de leche that’s easy to pipe, fill cookies, and will be able to hold its shape, cook for 3.5 to 4 hours.

Let the can cool down all the way in the water before removing and opening, which may take a few hours.

Remove the label of the can. Keep the can sealed.

Inspect the can to ensure it doesn't have any dents.

Place the sealed can in an instant pot or pressure cooker, filled up with water to capacity.

Set the pressure for high.

After 35 minutes, turn the pressure cooker or instant pot off. Let the pressure release naturally. And let the can cool down all the way in the water before removing and opening, which may take a few hours.