Sift together dry ingredients and set aside. In mixer, combine canola oil, coffee, half-n-half, and sour cream. Mix on low 30 seconds. Slowly add in dry mixture and mix on low until incorporated. Add in vanilla and mix. Add in eggs, one at a time, and mix just until combined.
Prepare 3 - 8 inch cake pans by spraying with baking spray, lining the bottom with a parchment circle, and the lightly spraying the circle with baking spray. Line cupcake tins with paper liners, and lightly spray with regular cooking/baking spray.
Pour batter into cake pans and lined cupcake tins 2/3 of the way full.
Bake at 350 for 13-15 minutes for cupcakes, or until a toothpick comes out clean. Let cakes bake for about 25 - 30 minutes. Use your best judgement and the toothpick test as your guide. Oven times and temperatures vary!
Let cakes and cupcakes cool for 15 minutes, and then remove to wire racks. Let cool completely before frosting.
Frosting:
Put room temperature butter in a mixing bowl and beat until smooth.
Sift in cocoa powder and powdered sugar, mixing and taking care not to leave lumps. Add vanilla, and mix.
In a different bowl, mix together Ovaltine and heavy cream until the ovaltine is completely dissolved. Slowly add to butter mixture. Beat on high for 1-2 minutes, or until frosting slightly lightens in color. Scrape down the sides of the bowl when necessary.
Ganache:
Heat your heavy cream and butter until almost boiling. Pour over chocolate chips in a metal bowl and stir well until the chocolate is completely melted. Add the 2 tsp vanilla and stir to combine.
Cool and whip 2/3 of the ganche. Leave the remaining 1/3 at room temperature.
For Decorating:
Spread whipped ganache between cake layers. Ice cake evenly with frosting. Make a depression in the top of the cake if you will be doing a number on top. Space chocolate chips evenly around the edge of the cake. Chill cake for 30-40 minutes in the fridge. Pipe frosting using a large star tip onto cupcakes.
Drizzle ganache around the edges, letting the excess fall down the sides. Fill the depression on the cake top with ganache. Use a toothpick or the tine of a fork to fill all the gaps without overflowing the form. Drizzle ganache over cupcakes. Decorate both cake and cupcakes with chocolate sprinkles