Preheat your oven to 350°F (175°C).

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.