Chocolate spice cake layers with chocolate spice buttercream.
Preheat your oven to 325 degrees F. Spray a 9"x13" pan with nonstick spray. Line the bottom with parchment paper if you plan to turn the cake out of the pan to serve. Otherwise, spray alone is ok.
In a medium size mixing bowl, combine the flour, cocoa, cinnamon, allspice, cloves and salt. Whisk to combine and then set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugars together on medium high speed for about three to five minutes, making sure to scrape the sides and bottom of the bowl occasionally. We want the butter mixture to get light and fluffy.
Add the eggs and beat again for a couple minutes.
With the mixer on low speed, alternately add the flour mixture and the buttermilk, starting and ending with the flour mixture. Mix until no flour streaks remain.
Fold in the sour cream.
In a small bowl, combine the vinegar and baking soda. Let bubble and then fold into the batter.
Pour the batter into the pan and bake at 325 for about 25 to 28 minutes, or until a toothpick inserted in the center of the cake comes out with a few moist crumbs on it.
Let cool completely before frosting.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter for a couple minutes on medium high speed.
While the mixer is beating the butter, heat the heavy cream in the microwave. Pour the heated cream over the chocolate to melt the chocolate. Stir until smooth. Set aside to cool a bit.
With the mixer on low speed, gradually add the powdered sugar, spices, and pinch of salt.
Scrape the sides of the bowl and then with the mixer on medium speed add the chocolate ganache you've made. Once all of the chocolate is added, turn the mixer to medium high speed and beat for about 3 to 5 minutes.