Preheat oven to 350 degrees. Grease a 9x5-inch loaf pan.
In a large bowl whisk together the flour, sugar, baking powder, salt, baking soda, cinnamon, and nutmeg. Set aside.
In a medium bowl whisk together the mashed bananas, eggs, butter, yogurt, and vanilla until combined. Fold banana mixture into flour mixture until just combined.
Bake for 55 minutes, until a toothpick comes out clean. Cool 30 minutes in pan, then turn out onto rack to cool completely.
Chocolate Glaze
Sift sugar and cocoa into a small bowl. Whisk in milk, vanilla, and salt all until smooth. Pour onto cooled bread and let set, 15-20 minutes.