Preheat oven to 190C/170C fan-forced. Grease an 8-hole 3/4 cup-capacity mini loaf pan. Line base and 2 long sides with baking paper, extending paper 1cm above edges of pans.
Sift flour, bicarbonate of soda and cinnamon in a large bowl. Stir in sugar. Whisk buttermilk, oil, eggs, vanilla and mashed banana in a medium bowl. Add buttermilk mixture to flour mixture. Stir until just combined. Fold in blueberries.
Spoon into prepared pan holes. Smooth top. Arrange extra banana over batter.
Bake for 15 minutes or until a skewer inserted into centre of each loaf comes out clean. Cool in pan for 5 minutes. Turn, top-side up, onto a wire rack to cool completely. Store in an airtight container at room temperature.
