Banana & Cocoa Cake

This banana cake has a very different texture compared to the one I normally bake. Very spongy and light... and yet very moist. Is it because I changed some ingredients or method? I'm not so sure. One thing I did very differently from my normal method was to use an electric hand blender which I use for making smooth soup. Blitz ..... By  mixing the wet ingredients by blender, the mixture became very fluffy and smooth.... like a banana smoothy texture. Anyway, this cake contains sunflower oil instead of butter or margarine, so it keeps the moisture longer... so I heard. 

Ingredients

• 175g caster sugar
• 175g plain flour
• 2 tsp baking powder
• 4 tbsp cocoa powder
• 80ml sunflower oil
• 70ml milk
• 2 eggs
• 1 tsp lemon juice
• 2 bananas (200g ish)

For crumble topping

• 30g Plain Flour  
• 15g Granulated Sugar (or Demerara Sugar) 
• 15g Butter (or low-fat margarine) 
• walnuts  

Method

1. Heat oven to 160C/140C fan/gas 3. Grease and line a 2lb loaf tin with baking parchment.
2. Mix the sugar, flour, baking powder, and cocoa in a large bowl.
3. Mash the banana in a bowl and add oil, milk, lemon juice and eggs. Then mix thoroughly with the electric hand blender.
4. Put the wet mixture into the dry mixture and mix gently.
5. Pour the mixture in the tin and sprinkle the crumble topping. (put the all ingredients for the topping in a bowl and make a breadcrumb like texture using your finger tips)
6. Bake for 50 minutes or until a skewer inserted comes out clean.