Why does my cake look like a mushroom?

Wow... I wish I knew more about the science of baking to be able to help you.
Unfortunately, I'm no help but I'm quite certain that whoever is able to help would need to know your recipe.

When you stack your cake pans do they nest inside each other?

Do you use Bake-Even strips? I make my own with a few layers of newspaper folded to about 1.5 inches, soak with water, and cover with aluminum foil. Hold on the cake pan with a binder clip.

No amount of bake even strips will help if the pans in use are larger in diameter at the top than they are at the bottom, and going by the picture the OP has offered, this is part of her issue. 

 

You're right, of course. The reason I suggested the strips was, I see the slanted part, but she said the top did not go over the pan, so I was picturing the "waist" in the middle of the layer.

The top is most likely slanted like that because the cake is bottom side up.

I would suggest a recipe or mixing flaw, since you said you make other cakes just fine, and I assume you use the same pans.

Perhaps the liquid ratio is too little in the recipe?

Oh, I understood where you were coming from.  Sorry if I came off catty (pun intended given your avatar), didn't mean to though on re-reading I could see me sounding like a right b**** kitty. 

 

The bane of novice bakers is the nesting cake pans.  So much easier to store in the cupboard, but you always wind up with a cake that slopes toward the bottom.  Felt entirely stupid when I read that explanation on the net, because I'd blamed my recipes and myself for years.  The worst of it was, the pans I had were actually made by Wilton who you'd think would know better.  I still have the Wilton checkerboard set that has THREE that nest together.

This use to happen to me all the time. I started using those bake even strips and it helped with the problem. Hope this helps.

I've read that you can make those strips yourself. I think people just cut a towel into strips, wet 'em, and then safety pin 'em around the pans. You might to be careful of stray fibers though...

I have the home made strips and they work well.  I took an old bath towel and cut it into a long strip.  If you have 2 inch high pans then cut your strips 4 inches wide.  If you have a serger or sewing machine fold them in half lengthwise and sew them.  It just makes them a little easier to handle, this isn't necessary.  So use the 2 inch wide strip, if you don't have a  sewing machine just fold it in half.  Wet the strip, wring it out, place it around your pan, then use a T pin, safety pin, any metal  pin or a metal binder and attach the strip tightly.  I roll up the extra length into a coil and place it next to the pan.  Then bake.

I too am a fan of the bake even strips, but my understanding was that they slowed the baking time at the edges so the outer edges would cook more slowly and have time to rise more. Thus a more level cake. Your cakes have a larger diameter on the top than on the bottom. Either the top is spreading or the bottom is shrinking. That's a tough one. Is your cake super moist and heavy? Maybe it flattens and spreads after coming out of the pan. do you let them cool before taking out of the pan? That seems like a lot of eggs for a chocolate cake.

If you would like to try a different recipe, this is my absolute favorite. I have made it a hundred times with no problems. 1 recipe makes 2 1.25 " deep layers. 1.5 times the recipe for 3 9" pans or an 11 by 15" pan. It freezes beautifully, and is light in texture but has a rich chocolate taste. This was the winner of an extensive taste comparison of chocolate cakes I did last year. It is from the softasilk cake flour box. Another excellent chocolate cake is the double chocolate layer cake on epicurious.com. They are equal in my book but the epicurious recipe has more ingredients and takes a bit longer. It does not use cake flour if that is not available to you. It uses regular flour.




Deluxe Devil's food cake
2 cups sugar (14 oz,400 gms)
2 sticks room temp butter (225 gms)
1 tsp vanilla
3/4 tsp almond extract
2 large eggs
2 1/2 cups sifted cake flour (8.25 oz, 250 gms)
1 cup Hershey's special dark cocoa
1/2 tsp salt
2 tsp baking soda
2 1/4 cups full fat buttermilk, room temp


Beat sugar butter and extracts for several minutes until very light and fluffy. Add eggs one at a time mixing well after each. Whisk together dry ingredients. Add dry ingredients in thirds, alternating with half of the buttermilk, beginning and ending with flour mixture. Mix after each just until combined. Scrape down well and mix one more minute. Pour into prepared pans and bake 350 (325 convection) for 25 to 30 mins

HTH!