Dutch process or not?

I agree with RachelIS. My cocoas of choice are either Green&Blacks or Cocoa Camino natural cocoa powders.
You can really taste the difference in the quality of the cocoa you use.

I would probably use natural cocoa powder for guaranteed good flavor. Dutch processed cocoa sometimes results in a darker colored baked good but it doesn't always taste better than natural cocoa (and sometimes tastes metallic)! Valrhona makes an excellent natural cocoa that tastes great and is very dark when baked. Good luck!

If recipe does not specify and it has leavening in it (baking powder or soda), I would assume natural. Is there a picture of the cake? Is it very dark?