Preheat oven to 180 C, 10 mins before baking. Grease and line a 9x5 loaf pan and set aside.
In a large bowl, whisk together eggs, buttermilk and oil until well beaten together.
Add in mashed bananas, both sugars and vanilla and mix well.
Sift in flour, baking soda and salt and mix in nicely, do not over mix.
Add chocolate chips and fold in gently.
Pour into greased loaf pan and bake in the preheated oven for about an hour (refer notes). Check at an hour by doing the toothpick test. Bake longer as needed until cooked through.
Notes
The original recipe uses 1 cup white sugar and 1/2 cup brown sugar and no chocolate chips. I used only brown sugar and added semi sweet chocolate chips. The sweetness was just right for our taste. To substitute buttermilk, add 1 tsp vinegar or lemon juice in a measuring cup and add milk to make it 1/3 cup. Let it rest for 5-10 mins. I got one big loaf and 1 small loaf from the above qty. You can also bake this as muffins, if you like. My bread was ready in 45-50 mins. Keep a close watch after 40 mins of baking. You can store the banana bread in an airtight container at room temp for 3-4 days, unless you are living in extreme humid places.