Separate eggs and store egg whites for another use.In a small bowl, mix egg yolks with sugar and cornstarch.
Add egg yolk mixture and half and half to a medium saucepan. Heat over medium-low heat for 5 minutes.Increase heat until it begins bubbling. Let it bubble for 1 minute.
Remove pan from heat and whisk in butter and vanilla.
Pour into a bowl. Cover tightly with plastic wrap, pressing the plastic wrap directly against the custard. Refrigerate for at least 2 hours.
Making the Cake
Preheat oven to 350 degrees. Spray two 9-inch cake pans with nonstick spray. Line with parchment circles and spray the parchment as well.
Separate egg whites from egg yolk. Save egg yolk for later in the recipe.Place egg whites in a mixing bowl. Using the whisk attachment of your stand or hand mixer, beat on high speed for several minutes, until stiff peaks form. (See notes under step 3 of the blog for tips on how to know if you have stiff peaks.)
In a separate bowl, mix together cake mix, egg yolks, milk, butter, and pudding mix and beat for 2 minutes.Gently fold in egg whites.
Evenly pour batter into the cake pans. Bake 25-28 minutes, or until a toothpick inserted comes out clean.Cool for 5 minutes. Remove the cake from pans and cool completely.
Making the Chocolate Ganache Frosting
Heat cream, corn syrup, and chocolate in a small saucepan over medium heat. Stir continuously until the chocolate is completely melted. Remove pan from heat and stir in vanilla. Use immediately.
Assembling the Cake
Place one layer of cake onto a cake plate or serving platter.Spread the custard over the top of the cake layer, spreading to the edges.Place the second cake layer on top of the custard.Pour the ganache onto the center of the top cake layer. Once all of the ganache has been poured onto the cake, use a spatula to spread to the edges. Allow some of the ganache to drip down the sides.
Refrigerate the cake for at least 2 hours before serving. This can be made up to 24 hours in advance.
The nutritional facts provided are only estimates. The accuracy of the nutritional information for any recipe on this site is not guaranteed.