Preheat oven to 350 degrees F. Spray two 9x5-inch loaf pans with baking spray and set aside.
In a large mixing bowl, beat butter and sugar with paddle attachment. Add in eggs and vanilla and beat until well combined.
Add in bananas, mix until blended. Add in flour, cocoa powder, baking soda, and salt. Mix on low, adding in the sour cream as it blends. Once everything is blended, stop mixing.
Fold in 1 1/4 cup of the chocolate chips. Pour batter into prepared loaf pans. Sprinkle the tops with the remaining 1/4 cup of chocolate chips.
Bake bread for one hour. Remove and cool in pans for ten minutes. Remove from pan and cool completely on a wire rack.
Notes
Sour cream can be swapped with full fat yogurt or Greek yogurt. Avoid choosing flavored yogurts as they contain extra sweeteners that can affect the taste and texture.
Store- keep bread in airtight container at room temperature for up to a week (I use a ziploc bag).
Freeze- wrap cooled banana bread in foil, then slide into a freezer safe ziploc bag and store for up to 3 months. Thaw on counter overnight.
Make muffins- Spray muffin tins with non-stick baking spray. Fill about 2/3 full with batter and top with extra chocolate chips. Bake for 17-19 minutes. Recipe makes about 36 regular sized muffins.