Prepare the sweet potatoes: Peel and grate the sweet potatoes using a box grater or food processor. Place the grated sweet potatoes in a clean kitchen towel and squeeze out as much moisture as possible.

Mix the ingredients: In a large bowl, combine the grated sweet potatoes, grated onion, beaten eggs, flour, salt, black pepper, and cinnamon. Stir until well combined.

Heat the oil: In a large skillet, heat about 1/4 inch of vegetable oil over medium-high heat until shimmering but not smoking.

Form the latkes: Take a small handful of the sweet potato mixture and form it into a flat patty, about 3 inches in diameter. Repeat with the remaining mixture.

Fry the latkes: Carefully place the patties in the hot oil, working in batches to avoid overcrowding. Fry for 3-4 minutes per side, or until golden brown and crispy.

Drain and serve: Transfer the fried latkes to a paper towel-lined plate to drain excess oil. Serve hot with sour cream or applesauce on the side.