To Make the Loaf:
Preheat the oven to 350 F. Grease a 8x4-inch and line with a sheet of parchment, leaving sides coming up the sides for easily removable. (A 9x5-inch loaf pan will work too but the loaf will be a bit stouter in shape!)
In a medium bowl, mix the flour, white sesame seeds, black sesame seeds, and salt until combined.
In a large bowl, whisk together the melted butter and sugars. Crack in the egg, pour in the vanilla and tahini and whisk until thoroughly combined.
Add the mashed bananas and baking soda and give it another good stir.
Add the flour mixture to the butter mixture, stirring just until the speckles of flour disappear. Be sure to scrape the bottom of the bowl to get any bits of flour that might be hiding.
Pour the batter into the prepared loaf pan. Give the pan a couple of moderate smacks on the counter to even out the batter.
Sprinkle the top with the sesame seeds. I added more to the center and then added only a few to the outside. I just liked the way it looked, no real reason!
Transfer to the oven to bake for 45 to 50 minutes, or until the center has risen, the edges are golden brown, and a skewer inserted into the center comes out clean.
Allow the bread to cool for 5 minutes in the pan, then invert the loaf and cool it on a rack, or live on the edge and eat it warm. The banana bread will stay delicious and moist for 3 to 5 days when wrapped tightly in plastic wrap.