Originally Posted by deMuralist
my chocolate cake recipe has 2C of flour and 1 3/4 C of sugar (so the reverse of what your first one had)
and mine does not use the baking powder, and I use natural (not dutch processed) cocoa, also, mine doesn't add the milk, but still uses the water.
(I use the Hershey recipe).
It may look like the first recipe has too much sugar to flour, but it is not because of the cocoa powder. Cocoa powder acts like a starch in a cake mix, so you add the weight of the two together to see how it compares to the weight of the sugar. In this case it is not so far apart to cause the sinking. You can read more about this in the book Bakewise by Shirley Corriher.
I like the advice of the previous poster. I didn't realize that too much batter can cause the same thing. So maybe the way around that is to bake it longer if you add too much batter? That is a guess, just thinking out loud.