Preheat oven to 350 degrees and grease 4 mini loaf pans or 1 large loaf pan.
In a large bowl, combine the flour, baking powder, salt, and 1 cup sugar.
Add in the egg, milk, and vegetable oil and stir until just moistened. Set aside.
In a small bowl, combine the cinnamon/1/3 cup sugar.
Divide half the batter into each pan (if using mini), or half the batter into one large pan.
Sprinkle the half cinnamon/sugar mixture on top followed by remaining batter.
Top with remaining cinnamon/sugar mixture.
Place pan(s) into preheated oven and bake for about 25 minutes if using mini loaves, or 45-50 minutes if large pan.
While bread is baking, combine the butter, powdered sugar, cream cheese, and vanilla in a medium bowl.
Once bread is baked (toothpick comes out clean once inserted in center), remove from oven.
Allow bread to cool for about 5 minutes before removing from pans and placing on cooling rack.
Drizzle desired amount of frosting onto the loaves and serve! *You may want to microwave the frosting for about 30 seconds to get it to drizzle on easier.