I'm starting to come out from under my cloud of culinary doom:
Sunday night I decided to monkey around with my angel food recipe. I split the batter in half before the folding in of dry ingredients stage. Then I split the dry in half. To one half I added a scant 1/4 cup of Valhrona (sp?) cocoa powder. Folded in, then layered and swirled in the cake pan.
I knew that one tinkers with baking recipes at one's peril, and especially that angel foods are tempramental. I got lucky, though, it turned out great! The chocolate swirl was very dark and chocolate-y, unlike my attemps at chocolate angel food in years past. I attribute this to using high quality cocoa powder. I find that Valhrona cocoa makes a bigger difference in baked goods than the difference you find using higher quality whole chocolate.
If anyone finds angel food too sweet, this would be an interesting thing to try. The addition of dark, unsweet cocoa made the cake taste significantly less sweet.