Set a pot of water over high heat to boil. Scrub the outside of the potatoes with water and a bristled brush (no need to peel!). Dice into 1 to 2-inch pieces. Add the potatoes to the water and cook until tender when pierced with a fork, about 15 to 20 minutes.
Drain the water and puree the potatoes with an electric mixer or hand masher. Mix in the butter, syrup, and cinnamon until thoroughly combined and smooth being careful not to overmix.