Marble cake: a sweet meeting of chocolate and vanilla

The visit to a friend's house yesterday night was the occasion to try out a new cake recipe. I have always liked this "classic" of cakes, the marble cake, but never tried my hand at it before yesterday, and the result was appreciated by all the friends at the party.
I got inspired by the recipe on this italian blog, http://zirela.blogspot.com/2010/01/plum-cake-marmorizzato.html, but then I slightly modified it, as usual.

Here are the ingredients for a 28 cm long cake pan

• 150 g unsalted butter (this is always a challenge in Delhi, so I changed it to approximately 1 dl of vegetable oil).
• 250 g flour (maida)
• 200 g sugar (powder sugar is the best)
• 4 eggs
• 2 1/2 tsp baking powder
• 2 dl milk (I used low fat cow milk)
• 40 g cocoa powder (for example Cadbury)
• 2 tsp vanilla sugar (the brand is called Keya, you will find it in the spices section of Big Bazaar).

In a bowl mix oil/melted butter with sugar, vanilla sugar and eggs. Then add the flour and the baking powder, followed by 1 dl of milk. Mix well to make a smooth and creamy dough.
Prepare your cake pan, either by putting a parchment or baking paper into it, or by greasing it with a small amountt of oil or butter. Further you can dust it with maida flour for best results. I prefer using baking paper, because that makes it really sure that nothing will stick to the pan. However, I don't know yet where to buy baking paper in Delhi, but I have a multiple use paper from Switzerland for the time being. If anyone know a place where to buy it, please let me know.

Now pour half (or even a bit more) of the dough into your prepared cake pan. Then mix the cocoa powder with the remaining milk and add it to the other half of the dough. The last step is to pour the chocolate dough on top of the first one, then with a spoon you can delicately mix the whole mass, so that you get a nice "marble" design inside your cake.

Bake the cake at 180°C for 45 minutes on the middle grid of your OTG oven. Do not open the lid during the process because the cake will collapse! To check if the cake is ready, insert a toothpick or a knitting needle into  it. If it comes out clean, with no dough sticking to it,  your wonderful marble cake is ready!