Orange Marble Butter Cake

I wanted to bake a marble butter cake so I went through the recipes and decided to try this due to the description of the cake by the blogger.

Recipe from All That Matters with some modification.

Ingredients:
200g Butter
100g Sugar
1 tsp Vanilla Essence
3 Egg Yolk
2 tbsp Fresh milk
a pinch of salt

200g Cake flour
1 tsp Baking powder
* Sift together

3 Egg White
80g Sugar

1 tbsp Cocoa Powder (sifted)
2 tbsp Fresh Milk

*Mix thoroughly, warm up the milk if you find the cocoa powder difficult to dissolve.

Zest of 1 Orange

Method :
1. Beat butter, sugar, salt and vanilla essence until light and creamy.
2. Add in the egg yolk one at a time and beat until creamy. Add in evaporated milk.
3. Fold in sifted cake flour and baking powder.
4. Whisk egg white and sugar to a soft peak and fold gently into the creamed butter mixture.
5. Spoon about half of the mixture into a separate bowl. Add in the cocoa mixture and stir well.
6. Stir in the orange zest into the rest of the batter.
7. Drop alternate spoonfuls of mixtures into an 7" round pan. Use a chopstick to pull backwards and forward through the mixture.
8. Bake cake for 1 hour in oven at 180 deg.C or when the skewer comes clean.
9. Turn the cake onto wire rack to cool.

Verdict?
The cake has a weird taste, I do not how to describe the taste but just felt there was a funny taste, my helper shared the same view. I was quite sure the taste was caused by the orange zest, probably the orange was too old, according to my helper the orange has been in the fridge for more than 2 weeks. If is not because of the weird taste, this cake will definitely taste nice as the texture was fine and soft.