Grease and flour 3 8-inch round cake pans, tapping out excess flour.
In a mixing bowl, sift together the flour, baking powder, baking soda, and salt. This helps to aerate the mixture and ensures there are no lumps. Set aside.
In another mixing bowl, use a hand or stand mixer to cream the butter and sugar together until light and fluffy.
Add the eggs, one at a time, beating well after each addition to incorporate air into the batter. Add the banana and beat well to combine.
Gradually add the sifted dry ingredients, alternating with the buttermilk. Begin and end with the flour mixture. Mix until just combined, ensuring not to overmix.
Evenly distribute the batter into the prepared cake pans, smoothing the tops with a spatula.
Bake in the preheated oven for about 35 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cakes to cool in the pans for about 10 minutes before transferring them to a wire rack to cool completely.
Once cooled, frost the cake layers with Italian meringue buttercream.
Stack the layers and frost the outside. Decorate the top with banana chips.
Notes
Use overripe bananas for enhanced flavor and moisture.
Store the banana cake in an airtight container at room temperature for up to 3 days or in the fridge for up to a week.
If buttermilk is unavailable, make your own by adding a tablespoon of lemon juice or white vinegar to a cup of milk and let it sit for about 10 minutes.
Feel free to get creative with decoration - chocolate chips, nuts, or a drizzle of caramel sauce can also complement the flavor of the banana cake beautifully.