Preheat oven to 350 degrees F. and line a small bread pan with parchment paper or spray with cooking spray.
Place butter and sugar into a large mixing bowl. Stir until well combined and add sugar, egg, vanilla, yogurt and bananas mixing well. Stir in flour, cinnamon, baking soda and salt. Mix until just combined then gently stir in chocolate chips. Transfer batter to prepared pan. Bake for 50-60 minutes, until baked through. Test with a toothpick to make sure. Remove and let cool completely before slicing.