Preheat the oven to 325°F. Lightly grease a 9" x 5" loaf pan; or a 12" x 4" tea loaf pan. , In a large bowl, combine the butter, sugar, vanilla, cinnamon, nutmeg, baking soda, baking powder, and salt, beating until smooth. , Add the mashed bananas, honey, eggs, and sourdough starter, again beating until smooth. , Add the flour then the nuts, stirring just until smooth. , Transfer the batter to the prepared loaf pan, smoothing the top. Let it rest at room temperature for 10 minutes. , Bake the bread for 45 minutes, then gently lay a piece of aluminum foil across the top to prevent over-browning. , Bake for an additional 25 minutes (20 minutes if you're baking in a tea loaf pan). Remove the bread from the oven; a long toothpick or thin paring knife inserted into the center should come out clean, with a few wet crumbs clinging to it. The tester shouldn't show any sign of uncooked batter. If it does, bake the bread an additional 5 minutes, or until it tests done. , Allow the bread to cool for 10 minutes in the pan. Remove it from the pan and cool completely on a rack. , Store leftover bread, tightly wrapped, at room temperature for several days. Freeze for longer storage.