Dissolve the raising agent in the yoghurt and mix. To it, add the cottage cheese and beat it well with a mixer. While continuously whipping, add the eggs one by one, then the stevia, corn flour and beat the mixture until uniform.
Divide the mixture in 2 and color one with the cocoa. Pour the cocoa mixture into a suitable non-stick baking tin, top it with the white part and put it to bake in a heated 338°F (170 °C) oven, for about 25-30 minutes.
Serve this cheesecake cooled.