In a small bowl, stir together sugar and cinnamon.
Line a 9x5-inch loaf pan with parchment paper or foil, allowing the edges to hang over the sides. Lightly spray with non-stick spray.
Spread 1/3 batter in the bottom of the pan.
Scatter 1/3 of cinnamon-sugar mixture over the batter in the pan.
Spread another 1/3 batter evenly in the pan, and scatter another 1/3 cinnamon-sugar mixture over the batter.
Spread remaining batter evenly in the pan, and remaining cinnamon-sugar mixture over the batter.
Swirl lightly with a knife -- only a few swirls. About 3-4 figure 8s across the short edges of the pan.
Bake at 350 degrees for 45-50 minutes, or until edges and top are golden brown, and a toothpick inserted near the center comes out clean.
Remove to a wire rack to cool.
Allow to cool for 15-20 minutes (no longer or bread will stick), run a knife around any loose edges, and lift bread out by the parchment paper or foil edges.
Cool completely on a wire rack.
Remove parchment paper or foil, transfer to a serving platter, cut and serve.