Place sweet potatoes in a large pot and cover with water. Bring to a boil over high heat, then reduce heat and cover pot. Simmer sweet potatoes at a low boil for about 35 to 40 minutes or until just tender enough to insert a sharp knife without effort. Don't let them overcook.
Remove sweet potatoes to a cutting board and let sit until cool enough to handle.
In a small saucepan over low heat, melt butter with brown sugar. Add the salt and maple syrup. Continue to cook for a minute or two until nice and syrupy. Add the heavy cream and cook and stir for another minute or two. Remove from heat.
Spray a 9 x 13 or slightly larger baking pan with non-stick cooking spray. Using a paper towel, remove the skins from the sweet potatoes and discard. Slice the sweet potatoes into discs about 1" thick. Place half of the sweet potatoes in the bottom of the prepared baking pan. Sprinkle with half the cinnamon and then drizzle half of the butter/brown sugar glaze. Repeat with remaining sweet potatoes, cinnamon, and glaze.
Cover tightly with foil and bake in a 350 degree oven for 25 to 30 minutes or till heated through and bubbly.
Make Ahead Method: Follow directions as written. After covering with foil, refrigerate for up to 24 hours before baking. May need to increase baking time for up to 15 minutes if sweet potatoes are cold going into oven.