Marble Chocolate Cheese Cake

My first of this kind...just few pieces left for snapshot!

A:
180 g butter
170 castor sugar
3 eggs

B:
120 g all purpose flour
1.5 teaspoon baking powder
1 teaspoon bicarbonate soda
20 g cocoa powder

C:
250 g cream cheese
60 g castor sugar
1 teasponn vanilla essence
1 egg

Processes:
Sift ingredient B all together

Mixture A: Beat butter and sugar till fluffy, then add egg one by one - beat after each addition. Pour in the flour slowly and mix using wooden spatula until the batter is well incorporated.

Mixture C: in another bowl, mix all ingredient C and blend together until fluffy.

Line the square tin with baking paper, extend over 2 sides. Drop 3-4 large spoonfuls of mixture A to cover the whole first layer, then pour mixture C in a single layer over mixture C. Finish off with mixture A. Make sure the mixture is well spread evenly.
Bake for 50-60 min in 160 degree. Cool off completely before cutting.