Preheat the oven to 180°C (356°F). Line a 9”x9” baking tray with parchment paper.
Sift together the flour, baking soda, and salt. Set aside.
In a mixing bowl, add butter and sugar. Beat with an electric mixer for 3-4 minutes until creamy.
Add eggs, one at a time, beating for 1 minute after each addition.
Add vanilla and beat for an additional 30 seconds.
Add mashed bananas and beat slowly for 30 seconds.
Fold in half the flour mixture gently with a spatula, then fold in the other half.
Add milk and fold until combined.
Fold in the dark chocolate chips, leaving a few to sprinkle on top.
Pour the batter into the prepared baking tray and sprinkle the remaining chocolate chips on top.
Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Let the cake cool completely on a wire rack. Slice and enjoy!