In a large bowl, cream butter and sugar. Then mix in eggs, vanilla and sour cream.
In a separate bowl, whisk together flour, baking powder, baking soda, and salt. Slowly add flour mixture to sugar mixture and stir until combined. Fold in bananas and chocolate chips.
Pour into 2 (8x4") loaf pans and bake for 55 minutes. If using a 9x5" pan, you can put the batter into one pan, but you will need to cook 10-15 minutes longer. You want the bread to be lightly browned. If it's browning too fast, cover lightly with foil. Remove from oven once a toothpick comes clean.
Once the bread is slightly cooled, remove from the pan and place on a cooling rack.
Enjoy with a cold glass of milk!
To make muffins: Pour batter into muffin tins. This recipe makes 24 regular-sized muffins. Bake for about 20 to 25 minutes, until lightly golden and toothpick comes out clean. To make small loaves: This mixture will fill 4 small loaf pans. Bake for 35 to 45 minutes, until lightly golden brown and toothpick comes out clean.