Preheat the oven to 350 degrees F. Line the bottom of a 9x13 pan with parchment paper and thoroughly grease the sides. Sift (or whisk) all dry ingredients in a bowl.
Beat together the eggs, buttermilk, oil, and vanilla. Slowly mix in the dry ingredients, and whisk for two minutes. Once well combined pour in the hot water and mix well. Pour into the cake pan and tap the pan on the counter a few times to remove any large bubbles.
Bake for 20 minutes, or until toothpick inserted comes out clean. Allow the cakes to cool for 15 minutes, then flip out on a plastic board. Remove the parchment paper. If the cake looks even, place in the freezer. If the top is rounded, carefully flip the cake over (using another cookie sheet) and trim the top with a serrated knife, then freeze.
For the Whipped Pomegranate Cream:
Add the pomegranate juice and flour to a small sauce pan. Whisk until there are no lumps. Then heat over medium, whisking constantly until the mixture comes to a boil. Whisk and cook a few more minutes until it thickens into a paste. Remove from heat and place pan in the fridge to cool. Beat the butter and sugar in a clean mixing bowl, for 5-7 minutes, until fluffy and glossy.
Once cooled, add the flour mixture to the butter mixture and beat until light and fluffy 5 minutes. Spread the pomegranate cream evenly over the cake and return to the freezer.
For the Whipped Chocolate Cream:
Add the milk, flour, and cocoa powder to a small sauce pan. Whisk until there are no lumps. Then heat over medium, whisking constantly until the mixture comes to a boil. Whisk and cook a few more minutes until it thickens into a paste. Remove from heat and place pan in the fridge to cool. Beat the butter and sugar in a clean mixing bowl, for 5-7 minutes, until fluffy and glossy. Once cooled, add the flour mixture to the butter mixture. Pour in the vanilla and the cooled melted chocolate and beat until light and fluffy 5 minutes. Spread evenly over the top of the pomegranate cream. Return to the freezer.
Once frozen, trim the edges of the cake until very smooth. The cake will be about 8x12 inches after trimming. Then carefully cut the cake into 1-inch squares, 96 total. You may want to use a clean ruler to mark the top of the chocolate cream to make the pieces even. Return the cake squares to the freezer.
For the Pomegranate Poured Fondant:
Place the shortening and half the pomegranate juice in a large bowl. Microwave until the shortening has melted. Add 5 cups of powdered sugar to the mix and whisk until smooth. Add a little more juice and another cup of powdered sugar, whisk. The fondant should be smooth and glossy, thin enough to pour but thick enough to coat well, a little thicker than school glue. If you see shortening dots on the top, add more powdered sugar. It may take all the juice and as much as 8 cups of powdered sugar to even out--but not always. Rewarm and whisk before dipping the petit fours. The fondant needs to stay warm.
Before dipping, dust the bottoms of each petit four, so that crumbs don't fall in the poured fondant.
Place a petit four on a fork over the fondant bowl. Using a large spoon, scoop fondant over the top covering completely on all sides, then use another fork to carefully transfer to a drying rack. Repeat with all, rewarm the fondant if needed. Keep the remaining petit fours in the freezer, only removing a few at a time, so they stay completely frozen for dipping. If the petit fours thaw, the fondant won't stick.