ASo a couple I'm working with wants a dark chocolate cake, I've been hunting for a great recipe, but all the ones I've tried are either too light and crumbles or is a dense as a hockey puck! Does anyone have a good dark chocolate cake recipe that is tough enough to stand up to stacking and fondant, but won't break your teeth when you eat it? Please!

Here is a great recipe from my pastry arts class that is a good go to.  I didn't want to infringe on the copy rights by taking the recipe from the book, so I looked it up and found it online.  You can tweak it by adding some dark chocolate.  I think you will be pleased with the results. hth
 

Devil’s Food Cake – from The Modern Café

You are going to want to use an electric scale so that you're able to use this recipe because I broke it down into grams. Make sure that you use a really good cocoa powder.

This is one of my very favorite cakes that I learned to make while getting my degree in the Baking and Pastry Arts. I hope you enjoy it as much as I do.

Ingredients Needed: (make sure that all the wet ingredients are at room temperature.)

Sugar – 562 grams

Pastry flour – 161.5 grams

Bread flour – 161.5 grams

Cocoa powder – 151.5 grams

Baking powder – 5 grams

Baking soda – 2.5 grams

Salt – 1.5 grams

Eggs – 178 grams

Egg yolks (only) – 71.5 grams

Butter (melted, but cool) – 76 grams

Butter Milk – 327 grams

Coffee – 303.5 grams

1. Preheat your oven to 320 degrees and get your two 9” and spray them with Pam or your cupcake pans ready.

2. Sift all the dry ingredients onto a sheet of parchment paper or into bowl.

3. Bring all the liquids, including the melted butter up to 70°. Place the eggs and egg yolks in a bowl large enough to hold all the ingredients in the recipe, and then slowly whisk in the melted butter. Slowly whisk in the buttermilk and, finally, the coffee.

4. Whisk all the dry ingredients until liquid, whisking constantly until it is thoroughly mixed

5. Pour your batter into prepared cake pans or scoop even amounts into the cupcake holders in you pans.

6. Bake for 10 min., and rotate the cake pans, and then bake for 7 to 9 more minutes or until the cake springs back when gentle pressure is applied with your fingertips. Check doneness with a toothpick at the center of the cake pan or one of cupcakes. If you're not sure. Press the middle of the cake with your finger. If it springs back, it is done.

7. If you do not plan to use the cakes right away. Make sure that you wrap them twice in Saran wrap and label them with the date that you made them they will freeze to up to two months. Do not stack them