Clean the potatoes under cold running water. Prick them with a fork, and place on a baking dish and bake for 1 hour, or until a knife slides through nice and clean without any resistance. Remove skins, they should just slip right off. Put the potatoes through a food mill.
Put potatoes in a bowl and add egg yolks, flour, cinnamon, and salt and mix until combined. Be careful not to over-work the dough. Pinch off tablespoons of dough and roll into balls.
Preheat a fryer or a deep pot halfway filled with oil to 350 degrees F.
Take 1 sheet of phyllo dough and cut into 3-inch circles. Brush with butter and place a ball of sweet potato dough in the center and pinch into a purse at the top. Continue to do this using more phyllo and you have used all of the potato dough.
Place into hot oil to deep fry to a golden brown color. Place in a bowl of caramel sauce and dust with powdered sugar.
Combine the sugar and water in a saucepan. Stir over low heat until melted. Turn up the heat to medium-high and cook until caramel colored. Take off the heat and add butter and cream. Be careful, caramel may splatter. Set aside to cool.