Place a small pot over medium heat with the syrup, heavy cream and cinnamon stick. Bring the liquid up to a bubble then reduce the heat to low and simmer until thickened and reduced, about 15 minutes.
Place the sweet potatoes, carrots, onion, celery and bay leaf into a medium-size stockpot and cover them with cold water. Season with salt and place over medium-high heat, bringing the liquid to a bubble. Reduce the heat to medium and cook the potatoes until tender, 15-18 minutes.
Drain the cooked potatoes and discard the onion, celery and bay leaf. Transfer the potatoes and carrots to a food processor, add a splash of chicken stock and puree until smooth, adding more stock as needed to keep things moving.
Return the pureed veggies to the pot they were cooked in and add the cider, remaining stock (add as little or as much as you like to get the consistency you want), nutmeg, thyme, cayenne and some more salt and pepper. Simmer the soup until heated through and thickened slightly, 3-4 minutes. Stir the reduced maple cream into the soup and serve with Griddled Cheddar-Apple Dippers alongside.