Preheat oven to 350°. Grease (or line with parchment paper sling) a 9x5” loaf pan.
Whisk together flour, baking powder, baking soda, salt, spices. Set aside.
In a separate bowl, vigorously whisk together eggs and sugar until smooth and lightened in color, 2 minutes. Drizzle in oil while whisking to emulsify. Whisk in sour cream and vanilla, then mashed bananas, until fully incorporated.
Mix wet into dry with a spatula until just barely combined (stop as soon as no more dry streaks). Do not over mix.
Pour batter into prepared pan. Bake 55-65 minutes until top is cracked and deep golden brown, and a knife inserted into the center comes out with only a few moist crumbs. Start checking at 55 minutes, then in 5-minute intervals. If edges start getting too dark, cover top loosely with foil.
Let cool in pan 10 minutes, then tip out to remove. (You can leave it in the pan, but you might get a soggy bottom.) Wait at least 30 minutes before slicing—if you slice too early, it will release steam and dry out loaf. Ideally, leave overnight and slice for breakfast the next day
Bananas: Mash with a fork until smooth. Don’t leave any unmashed lumps—they’ll sink and look gray/gummy after baking. Aim for purée texture.
2 bananas = lighter loaf. 3-4 bananas = denser loaf. Don’t use more than 1 ½ cups (350g) of banana—it will get too dense.
Sugar: Use all brown, all white, or any mix. More brown sugar = darker, denser loaf with moist top. More white sugar = lighter, fluffier loaf with crisp top.
Fat: Use oil, not butter, for a loaf that stays perfectly moist for days. Butter will lead to a dry, coarse loaf.
