Grease oil in a baking pan and keep aside.
In a mixer, add 4 small banana and ½ cup sugar grind it into a smooth paste.
In a mixing bowl, add grinded paste and one egg beat well using whisk.
Add ¼ cup vegetable oil mix well.
Take a Siever, add 1 cup Maida,1 tsp baking powder, ½ tsp baking soda, salt and sieve well.
Mix the batter well without lumps.
Add 1 tsp vanilla essence mix well.
Add this cake mixture to the greased baking pan.
Add chopped nuts to the top of the cake.
Tap the pan twice to remove air bubbles in the batter.
Preheat oven at 180 °C for 10 minutes and bake the cake mixture at 180 °C for 30 - 40 minutes.
Take it out and insert a toothpick to check whether the cake is cooked or not. If the toothpick comes out clean, the cake is cooked. Otherwise, bake it for few more minutes.
Banana cake is ready to serve.