Preheat oven to 350°F. Grease a 9x5 inch loaf pan and line with a strip of parchment paper.
On medium speed of an electric mixer, beat together mashed bananas, yogurt (or substitute), tahini, melted butter and vanilla. Add sugars; beat until combined.
Whisk together the flour, baking soda, and salt , then stir into the banana mixture until evenly blended. Fold in chocolate.
Pour batter into prepared pan and sprinkle top with sesame seeds or nuts.
Bake at 350°F for 55 minutes or until a skewer inserted comes out clean. Let cool completely, then remove from pan.