Preheat oven to 375°. In a small bowl, combine flour, sugar and cinnamon. In another bowl, whisk egg, sweet potatoes and oil. Stir into dry ingredients just until moistened.
Fill 24 greased muffin cups or muffin liners two-thirds full. Bake until a toothpick inserted in muffin comes out clean, 15-18 minutes. Cool 5 minutes before removing from pans to wire racks.
In a small bowl, combine glaze ingredients; drizzle over warm muffins.