Preheat oven to 425º

Pour the condensed milk into a small glass baking pan

Place the pan in a slightly larger pan

Pour water in the 2nd pan so it is halfway up the side of the small pan, creating a bain-marie.

Place both on a half-sheet baking pan. This will help you avoid any steam from the bain-marie when you remove the pan from the oven.

Place the pan in the oven, whisking every 20 minutes. Add water to the bain-marie as needed.

Remove once the milk has thickened and turned caramel brown.

Using a spatula, scrape the sides of the small baking dish, then whisk into the dulce.

Refrigerate the remainder in the fridge. The remainder is what's left after you gobble down a few tablespoons for quality control.

Warm to serve.