Pour half of batter evenly into 2 greased and floured 8 x 3 3/4-inch loaf pans. Stir together sugar and cinnamon; sprinkle half of sugar/cinnamon mixture evenly over batter in pans.
Pour remaining batter evenly into pans and sprinkle evenly with remaining sugar mixture. Gently swirl with a knife. Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on wire racks for about 10 minutes.