Instructions

1. 1
   Preheat oven to 350°F.
2. 2
   Generously spray a deep 9-inch springform pan with nonstick cooking spray.
3. 3
   Melt the chocolates in a double boiler or in a microwave oven at low power.
4. 4
   Set aside to cool.
5. 5
   Sift together the flour, baking powder, salt, and cinnamon into a medium-size bowl.
6. 6
   Place the butter and sugar in a large mixing bowl and cream at high speed with an electric mixer.
7. 7
   Add the vanilla and the eggs, one at a time, beating well after each.
8. 8
   Pour in the cooled chocolate mixture, and beat well until everything is incorporated.
9. 9
   Add ⅓ of the flour mixture, and stir until it is just barely incorporated, then pour in half the milk.
10. 10
    Stir briefly, then repeat with another ⅓ of the flour and the remaining milk.
11. 11
    Add the rest of the flour mixture and stir just enough to blend. Don't over mix, or the cake will toughen.
12. 12
    Spread into the prepared pan and bake for 55 minutes, or until a toothpick inserted into the center comes out clean.
13. 13
    Cool completely before assembling and frosting.
14. 14
    Cut the cake into 3 equal layers, using a long serrated knife and a gentle sawing motion.
15. 15
    Spread mocha buttercream between the layers, and stack them evenly.
16. 16
    Spread more buttercream on the sides and the top.
17. 17
    Artfully sprinkle the top with extra cinnamon, cocoa, and confectioner's sugar, if desired.