In a small mixing bowl add Oreo crumbs and melted butter, mix until evenly damp. Press the mixture into the bottom of the pan and slightly up the sides of the pan. Bake for 12 minutes, then set aside to cool slightly.

Reduce the oven temperature to 300F.

In a large mixing bowl, add the cream cheese and sugar, whip until smooth. Mix in the cornstarch and until well blended on low speed.

Pour in the Baileys and heavy cream, continue mixing on low speed until well combined.

Add eggs one at time, beating slowly just until incorporated (scrape the sides of the bowl for eggs 1 and 2), but stop right after mixing in the last egg.

Pour the cheesecake mixture into the crust. Wrap springform pan in a couple layers of foil, then place in a roasting pan filled halfway with water. Bake for 1 hour and 25 minutes (the top should be partially set with the center lightly jiggly).

Shut the heat off and open the oven door just a bit and leave in for an additional 45 minutes.

After that, remove the cheesecake from the oven and let sit for 2 hours. Place in the fridge for 1 ½ to 2 hours or overnight.

Optional ganache layer, (keep the cheesecake in the fridge until ready to pour) add chocolate to a medium heat-safe bowl and set aside.

In a medium saucepan (it is better with a large diameter), heat whipping cream and over low-medium heat until it is actively simmering but not boiling. Stir occasionally to prevent any sticking, but not too much to cool it down.

Transfer the warmed liquid over top of chocolate, then add 1-ounce Baileys and allow it melt on its own for about 5 minutes, then whisk until smooth.

Wait about 8 minutes for the ganache to thicken slightly, then remove cheesecake from the fridge, and springform pan (if needed run a sharp knife around the edge to loosen).

Pour chocolate ganache on the top of the cheesecake and spread as desired.