Line muffin tins with paper liners, or if making loaves, lightly spray pans and then line with parchment paper, leaving a 1/2" edge above pan.
Preheat oven to 350º
In a small bowl, combine the dry ingredients: flour, salt, baking soda and nutmeg.
In a stand mixer bowl, using a whisk attachment, combine brown sugar and butter and beat at medium speed until light and fluffy, about 1 minute. Add eggs one at at a time, beating between additions. Add mashed bananas and yogurt and beat to combine. Reduce speed to medium low and add flour mixture a bit at at time, mixing just until combined. Take care not to overmix. Scrape batter into prepared pan (s).
Bake for 20-35 minutes (depending on pan size) or until a toothpick inserted in center comes out with a few moist crumbs clinging. Place pans on rack and cool slightly.