Preheat the oven to 400 degrees F. Place the sweet potatoes in a large saucepan and cover with water. Bring the water up to a boil and blanch the potatoes for 3 to 5 minutes. Remove the potatoes from the stove and drain. In a large saute pan, melt the butter. Stir the cane syrup and brown sugar into the melted butter. Add the pecan pieces and cook for 3 minutes, stirring constantly. Turn the potatoes into a mixing bowl. Fold the pecan mixture into the sweet potatoes. Season the potatoes with salt. Blend to coat the potatoes evenly. Pour the potatoes onto a parchment lined 1/2 sheet pan and roast the potatoes for 15 to 20 minutes or until the potatoes are caramelized and tender.