For this wonderful cake, I used this recipe: Flourless Chocolate Cake Recipe | Epicurious.com
For the ganache topping:
1 cup heavy cream
1-1/2 cups 72% dark chocolate bar, chopped, or dark chocolate chips
1/2 cup cinnamon chips
Allow cake to cool completely.
Gently heat cream in a small saucepan over medium heat; do not allow to boil. Remove from heat. Add chocolate and cinnamon chips a little at a time and whisk until smooth. Pour over cake and smooth out with a spatula.