Place the unopened can on its side in a slow cooker.
Add water to slow cooker until can is completely covered.
Set slow cooker on "low" and cook for 8 to 10 hours
After the time is up, remove the can from the slow cooker and LET THE CAN REACH ROOM TEMPERATURE BEFORE OPENING
Whip dulce de leche with a wired wisk (for smoothness) and transfer to a glass jar.
Notes
Cooking for 8 hours will give you a lighter and milder flavor dulce de leche, while cooking it for 10 hours will give you a darker, richer flavor dulce de leche.You could add 1/2 teaspoon vanilla extract to the finished dulce de leche for a special touch of flavor.