Add the ingredients to a medium bowl and mix until fully combined.
Press the mixture onto the bottom and sides of a 9 or 10 inch springform pan. Use a measuring cup to press the mixture, it makes the process very easy. Refrigerate for 20-30 minutes.
Gelatin Mixture:
In the meantime, add 2/3 cup of cold water to a small bowl, sprinkle the gelatin on top. Let it bloom for 1-2 minutes. Whisk to combine, microwave for 30 seconds and whisk until fully combine and a gelatin mixture is formed. Set aside.
Cheesecake Filling:
Add the 20 ounces of chopped chocolate to a medium bowl, heat 1/2 cup of heavy whipping cream until hot and pour over the chocolate. Let it stand for 1 minute, stir to combine. If needed microwave for 30 seconds and stir until the chocolate is fully melted. The mixture should be smooth and shiny. Set aside to cool.
In a large bowl, using an electric hand mixer or stand mixer, beat cream cheese, add sugar on medium-low speed until combined. Stop a few times to scrape the sides and bottom of the bowl.
Add cocoa powder and mix until combined.
In a chilled mixing bowl, add the remaining 2 cups of cold heavy whipping cream. Whip on high speed until stiff peaks form.
Manually, using a spatula, fold the whipped cream into the cream cheese mixture. Make sure it's all combined, beat on low speed for 1-2 minutes.
Add in the vanilla extract and gelatin mixture to the bowl, mix on low-medium speed to combine.
Add the melted chocolate to the batter, mix on low-medium speed to combine. Using a spatula scrape the sides and bottom of the bowl.
Spread the cheesecake filling onto the prepared pan. Level the top with a spatula.
Set the cheesecake in the refrigerator to chill and firm, 6-8 hours or better, overnight.
Chocolate Ganache:
Add chocolate and corn syrup to a medium bowl.
Heat heavy cream in the microwave for 1 minute, until hot.
Pour hot heavy cream over the chocolate, let stand for 1 minute and using a spatula stir well until all the chocolate melts and the mixture is shiny and smooth. If needed, microwave for 20-30 seconds to melt any remaining small lumps.
Let cool to room temperature, but not to harden.
Pour chocolate ganache over the cheesecake and distribute evenly using a spatula.
Garnish with chocolate whipped cream roses and chocolate sprinkles.