Combine all ingredients and beat until smooth. Pour into a bowl that is wider than the rosette iron. Heat the oil to 360 degrees. Use a thermometer or do the "bread test"*. Heat the rosette iron in the oil at the same time. Remove the iron and let excess oil drip off. Dip in the batter. Hold over the deep fryer to set the batter a little. Deep-fry until golden, around 1 minute. Loosen from the iron with a fork. Drain on paper towels. Reheat the iron before frying the next rosette. Dip the rosettes in sugar.
* Place a cube of white bread in the hot oil. If it turns golden brown after around one minute, the temperature is correct.