Marble Cake (Marmorkuchen)

Wanting a simple, plain "Rührkuchen" today, I slighlty modified one of the so far untried recipes in Maida Heater's book called "Cakes". The recipe I used was the "Poppy Seed Cake", because I thought the recipe sounded good. Since I didn't have any poppy seeds, I decided to make it into a marble cake instead. 

Recipe changes:

I used a little more than 1 cup sugar (so the whole amount is reduced by almost 1/2/ cup),

I used 5 eggs, not 5 eggs and 1 egg white (throwing out an egg yolk seemed like a waste and I was not sure how to store it properly),

I used a mix of greek yoghurt and milk instead of sour cream,

I substituted 1/4 cup flour with ground almonds,

I left out the poppy seeds,

I made the dark batter by adding cinnamon and cocoa powder

The texture of the cake is pretty light, but not quite the tender crumb I wanted. Taste wise I wish I had added more cinnamon to the dark batter and more ground almonds in general. This would probably be great with the poppy seeds and some Eierlikör for flavor. Not a bad cake though and lots of potential for adding flavors. The book describes this as a mix of a sponge and a pound cake which describes the texture well.