Preheat oven to 180°C.
Mix eggs with sugar. Add yogurt, oil and finaly flour and baking powder.
Break chocolate into pieces and add to the mix.
Line a bread tin with greaseproof paper.
Bake for approximately 50 minutes. Watch baking process, put a knife into the cake and if it comes out clean, then it is cooked.
For a all chocolate version, you can add 5 tablespoons of black chocolate powder unsweetened.