Preheat oven to 425 degrees.
Scrub the sweet potatoes, but leave the skin on. Trim the ends flat. Cut ¼" circles (or smaller if you want thinner fries). Then cut the rounds into ¼" fry strips (or smaller if you want thinner fries).
Place them in a large bowl and drizzle oil on them. Sprinkle with salt, pepper and cinnamon. Mix them around until fully coated.
Lay them in a single layer on a parchment lined or well greased foil lined baking sheet. Bake for about 30 minutes or until they are to your desired crispiness.
Thinner fries tend to get crispier, but they won't get as crispy as fries that are cooked in a deep fryer. They will be soft in the center and absolutely delicious!
They are fantastic right off the tray, but I like to serve them with mayonnaise or mayonnaise with a little sriracha or chopped chipotle peppers mixed in if I am not keeping to an AIP diet. Ketchup is good too!