Place the granulated sugar and softened butter in the bowl of an electric mixer. Beat on high to cream, until the mixture is light and fluffy. Then scrape the bowl and mix in the bananas and eggs. With the mixer on low, slowly add the flour, salt, baking soda, and baking powder. Then scrape the bowl again and mix in the shredded coconut.
Scoop the batter into the loaf pan. Bake for 45-60 minutes, until a wooden skewer inserted deep into the center comes out clean. Allow the banana bread loaf to cool in the pan for 10 minutes. Then flip it out onto a cooling rack set over a piece of wax paper.
While the loaf is cooling in the pan, whisk the powdered sugar and Kahlua together until very smooth. Once you've flipped the loaf out of the pan, poke holes in the the top of the loaf with a wooden skewer to let the Kahlua glaze seep down inside. Then pour the glaze over the top of the loaf. You can use the wax paper to pour the drippings back over the loaf for an extra glaze coating, if you like. Allow the glaze to dry before cutting.
* Pro Tip if you can't wait days for your bananas to turn dark brown: quick-ripen them by popping the bananas in a 350 degree F oven for 5-8 minutes.