Preheat the oven to 180 degrees C for 15 minutes.
Grease a baking tray 8 by 8 inches with butter or oil.
Place a sieve on a large bowl. Add all-purpose flour, baking powder and salt and sieve the dry ingredients into the bowl.
1 1/3 cup all-purpose flour, 1 teaspoon baking powder, 1/2 teaspoon salt
In another mixing bowl, add melted butter, brown sugar, and white sugar. Blend with a cake beater or by just using a hand whisk. Mix well until the sugar melts and you get a creamy mixture.
1/2 cup melted butter, 1/2 cup brown sugar, 1/2 cup white sugar
Now add mashed bananas, eggs, yogurt and vanilla essence. Whisk well until everything is combined well as a batter.
1 1/2 cup mashed banana, 2 eggs, 1/2 cup yogurt, 1 teaspoon vanilla essence
To this add the dry ingredients (flour mixture) and mix well using a hand whisk.
Finally, add chocolate chips and mix well. Pour this batter into the baking dish.
3/4 cup chocolate chips
Bake the cake at 180 degrees C for 30 to 35 minutes.
Remove from the oven and set aside so that the cake cools down before cutting into pieces.