1. Set oven to 350°. Grease a loaf pan with butter and dust with flour.
2. In one bowl: flour + baking soda + salt.
3. In another bowl: sugar + oil +buttermilk +vanilla + egg + egg yolk.
4. Grab a handful of chocolate chips and melt in the microwave.
5. Pour wet ingredients over dry ingredients. Fold in mashed bananas, melted chocolate and chocolate chips.
6. Pour batter into pan and bake 60–65 minutes.
7. Test with a toothpick (no goop, unless it’s chocolate!).
8. Cool for 30 min, then cut.