Preheat oven to 350 degree Fahrenheit.

In a bowl, mix the dry ingredients (flour, baking powder and baking soda).

In another bowl, whisk together the eggs, sugar and softened butter. You can start by mixing the butter and sugar until well combined and then add the eggs and mix very well to make an egg butter sugar mixture.

Add the milk and vanilla extract to the egg butter sugar mixture and stir well to combine.

Mash the bananas in another bowl and add the mashed bananas to the mixture and mix well to combine.

Slowly add the wet ingredients mixture to the dry ingredients mixture and stir well.

Once this is done, add the blueberries to the batter and gently to blend the blueberries to the cake batter.

Grease the cake pan with butter and pour the batter into it.

Bake for about 45 to 50 minutes or until a toothpick inserted comes out clean. If the top of the cake browns before the inside is cooked, cover the top of the cake pan with an aluminium foil and bake for the remaining time. I covered the top of cake pan with aluminium foil after 30 minutes of baking and baked the remaining time with the foil on. The cake was done in 50 minutes of time, however since oven temperatures can vary, I recommend you to check with a toothpick inserted at the center of the cake after a total baking time of 45 minutes. Allow the cake to cool down in the rack before cutting.