Preheat the oven at 160ºC conventional oven and line a cupcake tray with 12 cupcake liners.
Sift together the all-purpose flour, baking powder and salt in a bowl. Mix together the buttermilk, vanilla extract. Mash the banana with a fork until smooth.
200 g all-purpose flour, 1 + ¼ teaspoon baking powder, ½ teaspoon salt, 50 g buttermilk, 1 teaspoon vanilla extract, 100 g very ripe banana
In a mixing bowl, using the paddle attachment add the butter and sugar and mix it on high speed for 1-2 min.
110 g butter, 210 g granulated sugar
Add the eggs one at a time into the mixture and mix it in until combined.
2 large eggs
Scrape down the sides of the bowl. Continue by adding ⅓ of the flour mixture, then the mashed banana, then ⅓ of the flour mixture and then the milk mixture, ending on the last ⅓ of the flour mixture. Mixing in each addition until just combined.
Using a rubber spatula, give the batter a gentle fold to make sure all of the ingredients has been combined.
Divide the cake batter into the 12 cupcake liners and bake them for 20-24 min or until a cake tester comes out clean.
Let the cupcakes cool on a cooling rack. After 5 min, gently remove the cupcakes from the cupcake tin and let them cool down completely.