1.) Peel and slice the potatoes into a bowl of cold water.
2.) Slice the onion into thin rings.
3.) Melt butter in a large skillet over med. high heat. Add the potatoes and onions. Lightly salt, pepper, and sprinkle cinnamon. Sautee for 5 min. making sure all the potatoes and onion get coated in the butter.
4.) Season lightly with salt, pepper, and cinnamon once again before covering the skillet and turning heat down to medium low.
5.) Cook covered for 20 to 30 more min.'s, uncovering only to turn the potatoes in the pan every 10 min's. Season once more very lightly during this time.
When potatoes and onions are caramelizing and tender the fries are ready.