Ingredients
Method
- Preheat oven to 350°F (175°C). Grease a 9x5-inch loaf pan and line with parchment. Whisk flour, baking soda, baking powder, salt, cream of tartar, and 1 tsp cinnamon.
- Mash banana, then stir in melted butter, ¾ cup sugar, eggs, vanilla, and buttermilk until smooth.
- Fold dry ingredients into wet just until no flour streaks remain.
- Mix swirl ingredients (3 tbsp sugar, 1 tbsp cinnamon, 1 tbsp flour). Spread half the batter in pan, sprinkle with all but 1 tbsp of the mixture, add remaining batter, and top with reserved cinnamon sugar.
- Bake 50-55 minutes until a toothpick inserted in center comes out with moist crumbs. Cool in pan 10 minutes, then lift out onto a rack.
- Cool at least 20 minutes before slicing. Serve warm.
Notes
The bread keeps best wrapped tightly at room temperature for a day; after that, refrigerate to preserve moisture. If your loaf browns too quickly, cover with foil for the last 15 minutes of baking.
