Preheat oven to 350 degrees. Generously grease a 9 loaf pan with cooking spray or butter.
In a large bowl, combine flour, 1/4 c sugar, baking powder, baking soda and salt. Set aside.
In a medium bowl, mash bananas and mix in vanilla and yogurt. Set aside. (Sorry guys, you'll need a total of three bowls for this. It's worth it!).
With your stand mixer or in yet another bowl, beat together remaining sugar (1/2 cup) and softened butter for about 3 minutes until light and fluffy . Add eggs, one at a time.
Turn the mixer to low and add a third of the banana mixture. Let mix until just combined. Add half of the dry ingredients. Continue alternating until all the ingredients are combined, scraping down sides if necessary. Try not to overmix.
Pour batter into prepared loaf pan and bake for about 55 minutes or until a skewer comes out clean.The book claims using this recipe above each serving (1 loaf divided by 10 slices) is 240 calories. That's compared to a standard banana bread recipe at 320. I usually cut the slices in half again which makes each piece only 120 calories. Not bad for a morning or evening snack.