For the Cake and Assembly Prep:

1. Preheat the oven to 350°F. Line a half baking sheet with a silicone mat or parchment paper. Lightly coat the sides of the pan with cooking oil spray.
2. Follow the recipe to make the cake batter, and spread it into the prepared baking sheet. Bake for 12-15 minutes, or until the cake is springy and a toothpick inserted into the center comes out clean.
3. Cool completely in the pan. Carefully cut out 3 or 4 6-inch rounds, depending on how tall you want the cake to be. Save any extra scraps for a future use. Cover the rounds, and set aside them aside while you make the cream.
4. Prep the cake ring before making the Bavarian cream. Place a piece of parchment paper that is slightly larger than the size of the cake ring on a plate or tray. Place the cake ring on top of the parchment paper. Line the interior of the cake ring with one strip of the acetate. Set aside.

For the Bavarian Cream:

1. Place 1/3 cup cold water in a small microwave-safe bowl. Evenly sprinkle the gelatin on top. Set aside to bloom as you prepare the custard.
2. Create a double boiler by first filling a medium saucepan about a 1/4 of the way full with water. Gently simmer the water without boiling. Leave the water simmering as you prepare the other ingredients.
3. Using a heatproof metal bowl that fits on top of the saucepan, whip the egg yolks and sugar off the heat with a whisk until thick and light yellow in color. In a separate small saucepan, scald the milk. Slowly pour the warm milk and vanilla into the egg yolk mixture, whisking constantly.
4. Place bowl that contains the milk and egg mixture on top of the lightly simmering pot of water. Gently cook, stirring continually with a rubber spatula until it thickens slightly, about 10-12 minutes. It should thicken enough that it coats the back of the spatula without quickly dripping off. Immediately remove from the heat, and pour the mixture through a strainer into a clean bowl to remove any cooked egg pieces.
5. When the custard is strained, gently melt the bloomed gelatin by heating it in the microwave for just a few seconds, until liquid. Stir the gelatin mixture into the hot custard mixture.
6. Cool the custard in the refrigerator uncovered, stirring occasionally. Chill until it is just beginning to set but is still very soft, about 30-40 minutes.
7. While the custard is cooling, prepare the whipped cream by whisking the cold heavy cream until soft peaks form. As soon as the custard is ready, gently fold in the whipped cream until it is completely incorporated.

To Assemble:

1. Working quickly, place one chocolate cake disc on the bottom of the prepared cake ring. If using three cake rounds, you’ll have two layers of Bavarian cream. Divide the Bavarian cream into two equal amounts, and evenly spread the first amount of cream on top of the cake round. Alternate with another cake round, then the other amount of cream, then top with the last cake round.
2. If using four cake rounds, you’ll have three layers of Bavarian cream.  Divide the Bavarian cream into three equal amounts, and evenly spread one third of the cream on top of the first cake layer. Continue alternating between cake and the other amounts of the cream, starting and ending with a cake disc.
3. If the cake is beginning to reach heights that go beyond the first layer of acetate, gently slide the second acetate collar between the first acetate layer and the cake ring to extend the border.
4. Follow the recipe to make the ganache. Pour over the top of the cake, smoothing out the top.
5. Immediately place the cake in the refrigerator uncovered to chill and set completely, for at least 2 hours.
6. When ready to serve, carefully lift off the cake ring, then remove the acetate. Slice, serve, and enjoy!