I've used this recipe many times. It drives me crazy though because when it turns out, it's the BEST cake I've ever had, but many times it falls, shrinks and becomes super dense. I'm thinking this is not nearly enough flour to support all the other heavy ingredients. Since it calls for a full cup of cocoa, I wasn't sure how much to increase the flour? Do you think it needs more baking powder or maybe even a little baking soda because of the buttermilk? The cocoa I use is 100 grams per cup.

1 cup butter softened 1/2 cup shortening 3 cups sugar 5 large eggs 2 cups cake flour 1 cup Dutch process cocoa 1/2 teaspoon baking powder 1/2 teaspoon salt 1 1/4 cups buttermilk 2 teaspoons vanilla extract

Step 1 Beat butter and shortening at medium speed with an electric mixer until creamy; gradually add sugar, beating until blended. Add eggs, 1 at a time, beating just until blended.

Step 2 Combine cake flour and next 3 ingredients; add to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed until blended after each addition. Stir in vanilla.

I usually do not do this, troubleshoot recipes -- but I would sub in some all purpose flour-- maybe swap out a cup for a cup -- yes it weighs a tiny bit more but that's ok -- or yes like you said add more of the cake flour -- but adding the all purpose will slightly toughen it and that sounds like what you need -- 

also I almost always beat any cake for two minutes after everything has been added on a speed four or five -- not cakes with folded in whipped egg whites -- but this recipe for sure I would ~

well there's a difference in the weight of the two flours just depending on how they are handled -- some charts show a cup of cake flour actually weighing more than all purpose -- so anyway ~

I'm gonna try that, most recipes state to only mix till incorporated, maybe I'm stopping too soon. Thank you

I mean yes lots of recipes say that — but think about if you only just incorporate the eggs and only just mix the whole thing for a bit while ingredients are being added — the eggs never get wound out — you want the volume and oomph they provide —

in fact after the eggs for that kind of recipe I usually do two minutes at a 4/5 speed in order to wind the eggs out and get the best emulsion possible — then I do the two mins after all is incorporated — ‘cause otherwise those ingredients are  just kinda well moistened and you need a bing bang emulsion, nice smooth batter for a good cake yes?

MamaGeese 

Where did you get the recipe? Wondering if the book/site had more detailed information? Gotta say, that’s a lot of sugar for a cake, and ditto for the cocoa per ratio of flour. I think if was making this, first I would mix the flour, baking powder, salt and cocoa well, set aside. I would beat the butter, sugar and eggs until light and fluffy. That will help give the cake lift. Then add the flour/cocoa mixture alternately with the buttermilk to the butter/sugar/eggs. Then beat on medium for at least 3 minutes. This would be a pretty dense batter. So would probably take 35-40/45 minutes, maybe a bit more @ 350 d in 8”/9” x 2”/3” pans. Does sound chocolatety and scrummy. 

Thanks for the tips ....when it doesn't fall it truly is the best thing I've ever eaten....with a sour cream chocolate ganache....OMG..it's a Southern Living grooms cake recipe. I use a dutched cocoa powder from a company in PA called Wilburs...it's the most beautiful cocoa, sometimes I just open the bag and smell it...

I made it again today...using all purpose flour instead of cake flour, and added an extra 1/4 cup. It still shrank just a tad, but it didn't fall! I cut the layers and the inside looked divine. Oh and I did mix it an extra minute or so after everything was incorporated...-K8Memphis might be onto something! Thanks y'all ❤️

Glad it turned out well!!!

yay!