About the egg white and substitute discrepancy: I can't remember the
reason but my guess is that using real egg whites in large quantity
relative to the rest of the ingredients makes the resulting baked
product more rubbery. (This last bit of information comes from Alice
Medrich's book "Chocolate and the Art of Low-Fat Desserts", a book I
love but which is unfortunately not fatfree) She mentions that she
made unbelievable rubbery brownies when she replaced 2 whole eggs with
4 whites but that they were excellent when she used 2 egg whites.
I don't think that the same thing happens when using a powdered egg
substitute but if you are using something that is pretty much an egg
white, I'd use the equivalent of only 2 whites.
Cocoa and peanut butter
I checked the FAQ in the web page and the recipe rules are dated
1994. I know that they've been updated more recently but I can't
remember if they've changed with respect to these ingredients
About the use of cocoa and peanut butter:
According to this list rules at the time, peanut butter was permitted
but in very limited quantities. You will notice that the entire 8x8
pan uses only 1 Tablespoon of peanut butter.
I don't know how it would be if the peanut butter was left out. It
does add a slight peanut taste to the brownies but leaving it out
would probably affect the texture. If you try leaving it out, I would
definitely try to use something like yogurt instead but I have not
I don't remember ever seeing that cocoa is not permitted. The only
thing about it was that it contained caffeine.