Preheat oven to 350 degrees F and grease 5 mini loaf pans or 1 large pan.
In a medium bowl, cream together the butter, sugar, salt, and cinnamon.
Add in the eggs, vanilla, and sour cream.
Add in the flour and baking powder stirring until just combined.
Fold in the chocolate chips (optional).
Pour batter (it will be thick) into the prepared loaf pans, filling about 2/3 full.
In a small bowl, combine the 3 tbsp sugar with 3 tsp ground cinnamon. Sprinkle mixture evenly on top of batter.
Place pans in oven and bake 30-35 minutes if mini loaves, or 60-65 minutes if large loaf pans.
Remove from oven and allow to cool slightly before removing from pan and serving!