Preheat the oven to 325 degrees F. Prepare two 8" round cake pans with non-stick spray, parchment and another coat of spray. Set aside.

In a medium size bowl, sift the cake flour, baking powder, and salt. Set aside.

In the bowl of a stand mixer, fitted with the paddle attachment, beat the butter, canola oil, and sugar on high until fluffy and smooth, about 5 minutes.

Add the eggs and egg yolks, one at a time to the bowl and beat on medium until well incorporated.

Turn the mixer on low and add 1/3 of the flour mixture to the butter mixture and mix until fully incorporated. Then add half of the sour cream and blend well, followed by another 1/3 of the flour mixture, the second half of the sour cream and lastly, add the remaining flour mixture and mix until incorporated.

Add the clear vanilla extract and butter extract and beat on low until incorporated. Scrape down the sides of the bowl and mix on low for another 30 seconds.

Evenly distribute the cake batter among the two pans (about 25 to 28 ounces in each) and bake for 40-45 minutes or until a toothpick inserted into the middle of the cakes comes out clean or with just a few crumbs. Make sure not to over bake.

Remove cakes from the oven and let cool in pans for 10 minutes before inverting onto cooling racks.

Once completely cooled, wrap in plastic wrap and place in the freezer or refrigerator to chill before frosting.

In a medium-sized mixing bowl, whisk the sugar and egg yolks. Add the cornstarch and whisk until the mixture is light yellow and a bit thick.

In a medium saucepan, heat the milk and vanilla. Just before the milk begins to boil, remove it from the heat.

Very slowly, add the milk to the egg mixture, whisking constantly to avoid curdling the eggs. When you’ve combined all the milk with the egg mixture, pour the mixture back into the saucepan and return to the stove.

Cook the mixture over medium heat until it has thickened, about 10 to 15 minutes. Make sure to stir occasionally.

Remove from heat and allow to cool completely. Cover and refrigerate overnight.

In a microwave safe bowl, heat the cream for about one minute. Pour the cream over the chocolate chips and let sit for about two minutes. Stir to combine and create a silky, smooth texture.

Let cool slightly before using on the cake.

Place the first cake layer, top side up, on a cake plate.

Evenly spread about 1.5 to 2 cups of the custard over the cake layer, being careful to not get too close to the edge of the cake.

Place the second cake layer, top side down, on the custard.

Carefully spread the chocolate ganache over the top of the cake, allow the chocolate to fall over the sides of the cake.