Preheat the oven to 180°C (350°F). Position a rack in the center of the oven.

Combine the milk and lemon juice in a small bowl and set aside.

In a separate bowl, whisk together the flour, baking soda, and baking powder. Set aside.

Using an electric mixer, beat the butter in a large mixing bowl on medium speed until creamy.

Add the sugar and mashed bananas and beat for about 20 seconds until combined.

Add the eggs, one at a time, beating for about 1 minute. Add the milk mixture and beat for another 20 seconds.

Sift the flour mixture over the wet ingredients. Scrape down the sides of the bowl and mix until just incorporated. Do not overmix.

Pour half of the cake batter into the prepared loaf pan. Arrange the banana slices evenly over the batter, then spread the Nutella over the banana slices.

Pour the remaining batter evenly over the top, covering the banana slices and Nutella.

Bake for 50–55 minutes, or until a knife inserted into the center of the cake comes out clean or with a few moist crumbs.

Remove the cake from the oven and let it cool in the pan. Carefully invert it onto a serving plate. Dust with powdered sugar, if desired. Slice and enjoy!