Adjust the oven rack to the lower third position and preheat the oven to 180C degrees (or 160C fan-forced). Lightly spray a loaf pan with nonstick spray. Set aside.
Using a hand-held or stand mixer, cream together the butter and brown sugar on medium speed, about 3 minutes. On medium speed, add the eggs one at a time, beating well after each addition. Beat in the yogurt, mashed bananas and vanilla on medium speed for 1 minute. Remove the bowl from the mixer if using a stand mixer. Set aside.
In a large bowl, toss the flour, baking soda, salt, and cinnamon together until combined. Using a large spoon or rubber spatula, slowly mix the dry ingredients into the wet ingredients. Slowly stir everything together until no more flour pockets remain. Do not over-mix. Gently fold in the raspberries and chocolate chips.
Spoon the batter into the prepared baking pan - sprinkle with a few additional chocolate chips if desired. Bake for 60-65 minutes, loosely covering the bread with aluminium foil at the 30 minute mark. This will prevent the top and sides from getting too brown. A toothpick inserted in the centre of the loaf will come out clean when the bread is done. Remove from the oven and allow the bread to cool completely in the pan on a wire rack before slicing.