Prep: Start by preheating the oven to 350 degrees F. Then, spray two 8 inch cake pans with non-stick spray and set aside.
Cake batter: In a large bowl, whisk together the cocoa powder and hot water until smooth. Set aside.
In a separate small bowl, sift together the flour, salt, baking powder, and baking soda. Set aside.
Then, melt butter/oil and sugar in small saucepan over medium-low heat. You can also melt the butter and sugar in the microwave if you want to save time.
Once melted, remove from heat, and transfer to a bowl of a mixer stand. Beat on medium-low speed until cooled, this could take up to 15minutes. You can also use a handheld electric mixer for this step, but it will require commitment and time.
Next, add the eggs, one at a time, beating mixture after each egg addition.
After that, stir in the vanilla extract and add the cocoa-powder mixture to the sugar/egg mixture. Reduce speed to low.
Now, start adding in the flour mixture in two batches, alternating with the sour cream and beginning and ending with the flour (1/2 the amount of flour, then all the sour cream, then the last half of the flour mixture). Beat until just combined, be careful not to over mix.
Bake: Proceed to divide the cake batter between the two prepared cake pans. Place in the oven and bake for 45-50minutes or until toothpick inserted into centers comes out clean.
After removing the cake pans from the oven, leave the cake in the pans for no more than 5 minutes, then transfer cakes to a wire rack to cool completely before frosting.
Buttercream Frosting: In a medium size bowl, cream together the shortening, clear vanilla extract and water or milk. Make sure it is a smooth consistency before moving on.
Then, add the confectioners sugar and pinch of salt. Blend together until nice and creamy. If you find that the frosting is too stiff, keep adding a tablespoon of water or milk until you reach the desired consistency. I added 3-4 extra tablespoons to make it really smooth.
Filling the Cake: To fill the cake, I cut the dome off the top of both the cakes, to make them flat. I placed the first cake right side up (with the cut dome on the top) on the cake platter. Then I put a layer of caramel sauce on bottom layer of the cake. I used about a half of a jar of caramel sauce (about 3-4 oz), this will absorb into the cake.
I then put a layer of the vanilla butter cream frosting on top of the caramel. Followed by a large sprinkling of white chocolate chips on top of the frosting. This can be as much or as little as you want, or you can skip this step if you don't want them.
Then, the next layer of cake I placed on top of the white chocolate chips. This was placed on the cake upside-down (with the cut side facing down).
Frosting the cake: For best results while frosting a cake I suggest starting on the top, get that covered and relatively smooth. Then work you way around the sides of the cake to cover them and make them smooth. I use a spatula with long, straightedges for this step. You can also use a butter knife, anything that has a long straight edge will work great.
Once the cake is frosted, put the rest of the caramel sauce in the microwave for 10-15 seconds. Then with a spoon slowly drizzle it around the edge of the cake, enough that it will run down the side of the cake. I went around the edge of the cake about 3 times to give it enough sauce for a decent drizzle.
Feel free to add a bit of flare to your cake if you want. I swirled rosettes around the edge of the cake and topped them with black fondant flowers and a pearl sprinkle. Once the cake is frosted and decorated to our liking, serve, and enjoy!