Preheat oven to 350 degrees. Spray two 9 inch cake pans with non-stick cooking spray. Place a piece of parchment paper in the bottom of the pan and spray with non-stick cooking spray.
In a microwave-safe medium bowl, add in the water and butter. Microwave for 2 and half minutes.
Add vegetable oil and cocoa powder in the water and whisk until smooth.
Add sour cream and vanilla extract and continue to whisk until incorporated.
In a separate bowl, add in cake flour, sugar, baking soda, and baking powder. Whisk until combined.
Pour the cocoa mixture in with the dry ingredients. Add in the lightly beaten eggs. I add the eggs now because I don't want them to cook in the hot cocoa mixture. Whisk until everything is combined. Try to whisk out most of the lumps.
Divide the batter into the two 9 inch cake pans. Place the peppermint patties on the top of the batter. You can either cut up the patties or place them whole.
Bake for 30 minutes or until they're done. Place a toothpick in the center of the cake and if it comes out clean or with moist crumbs it's done. If it comes out with batter, let the cakes bake an additional 3-4 minutes and test the cakes again.
Let the cake cool in the pan for about 15 minutes and then turn onto a cooling rack to finish cooling.
Frosting
In a large mixing bowl, add in the butter, powdered coffee creamer and peppermint extract. Mix on medium until incorporated.
Add in the powdered sugar and heavy cream and beat on low until the powdered sugar is incorporated.
Once the powdered sugar is incorporated, turn the mixter on high and beat for 3 minutes until light and fluffy.
Add the frosting to the cooled cakes. I filled my cakes and then did a very thin layer on the top and sides of the cake. Make sure the sides are filled in.
Refrigerate for 30 minutes until frosting is hard. Meanwhile make ganache to pour over top of the cake.
Ganache
Add the milk chocolate chips and heavy cream to a medium microwave-safe bowl. Place in the microwave for 30 second intervals. Stir after each interval. It will take about three 30 second intervals for the ganache to be completely smooth.
Set aside to cool for 10 minutes.
Pour the ganache over the chilled cake. This will leave a nice dripping effect on the sides of the cake.
Place the mini peppermint patties on the wet top around the edges. Once decorated, place in the fridge. The cake will have to be stored in the fridge because of the ganache.