Super simple I DO IT IN A NOT SO TRADITIONAL WAY, normally one would use a pot for this dish.
Me having my Cuban heritage consume tons of rice and always have my rice cooker handy and have learned to use for more things than rice.
YES I DO MAKE THIS IN A RICE COOKER, normally though one would do this in a pot on the stove, bring the water to a boil with everything and simmer on low. So don't worry if you don't have a rice cooker just do it on the stove.
In case you don't know "Piloncillo" is unrefined cane sugar in solid form also known as "Panela" for certain cultures, you'll find it in ANY HISPANIC SUPER MARKET,
If for some reason you cant find it use DARK BROWN SUGAR in it's place.
-8 small- medium Sweet Potatoes or 5 large ones or 5 long ones just look at the pics
-2 Cinnamon Sticks
(1)Clean sweet potatoes, remove edges and cut in half if it's to big to fit in rice cooker (I cut it)
(2)Throw in rice cooker with cinnamon, add enough water to cover the sweet potatoes 1/3 - ½ way. (I suggest 1/3 I did it half and it wasn't SUPER thick like I like, but ½ way will get you a real "maple syrup" consistency.) Then put the 2 "Piloncillos" on top (don't worry they will melt into the sweet potatoes and water with heat so don't trouble yourself
(3)Cover and turn on Rice Cooker and forget about it for 50 minutes.
(4)Uncover and it will be boiling FURIOUSLY, then let boil opened for 10 minutes to further reduce.
(5)Turn off rice cooker and your done leave there or transfer to a nice serving dish.