In a bowl, mix the eggs and yogurt.

Gradually mix in the flour and baking powder. Add the sugar and oil, and mix well.

Mash the bananas and add them to the mixture (I used 2 because they were large; if they are small, you can use 3). Also add the cocoa powder (I used a generic brand).

In a baking pan (greased with a little butter to prevent sticking), pour in the entire mixture.

Bake in the oven at 350°F (180°C) for 30-40 minutes.