Preheat oven to 350 degrees. Grease and flour one 9-inch loaf pan (or 3-4 small ones). Pan should be 3/4 full of batter.
In a large bowl, cream the butter with sugar until light and fluffy. Add the eggs and mix well.
Whisk together the flour, baking soda, and salt; combine with the butter mixture.
Add the sour cream, bananas, and vanilla; stir well.
Add in the chocolate chunks and mix in well until combined.
Pour into prepared pans and bake for 30-50 minutes (depending on the pan sizes). Test the center before removing from the oven, that the bread is done. You can use a cake tester or a toothpick.
Cool for 10 minutes and then turn the loaf out onto a rack, using a knife to cut around the loaf (for easy release).
Notes
TIP: This recipe makes 4 small loaves or 1 large loaf. Adjust cooking time depending on size of pans.Reposted from January 2014.