Preheat the #oven to 350 degrees Fahrenheit. Lightly grease a 9x5-inch #loaf pan{}.

Mix together @suger{1/3%cup} and @cinnamon{2%tsp} in a small bowl; set aside.

Combine @all-purpose flour{2%cups}, remaining @sugar{1%cup}, @baking powder{1%Tbsp}, and @salt{1/2%tsp} together in a #large bowl{}.

Combine @beaten egg{1}, @milk{1%cup}, and @oil{1/3%cup} in a separate bowl; add to flour mixture. Stir until just moistened.

Pour half of the batter into the prepared pan. Sprinkle with half of the reserved cinnamon-sugar mixture. Repeat with remaining batter and cinnamon-sugar mixture. Draw a #knife through batter to marble.

Bake in the preheated oven until a #toothpick inserted into the center of the loaf comes out clean, ~{45 to 50%minutes}.