Add dry ingredients to batter; beat slowly to blend. Mix at medium speed.
Fold in beaten whites until blended.
Mix 1/4 cup sugar and cinnamon. Pour half the batter into pan. Sprinkle with half the cinnamon mixture. Add remaining batter and sprinkle with remaining cinnamon mixture. Holding a knife vertically, draw blade through batter around tube.
Bake in 350° oven just until cake springs back when lightly pressed in center, 1 to 1 1/4 hours.
Cool in pan 15 minutes. Invert cake onto a plate. Serve warm or cool.