Preheat your oven to 325°F (160°C).
Prepare the crust by mixing graham cracker crumbs and melted butter.
Press the crumb mixture into the bottom of a springform pan, creating an even layer.
Bake the crust for 10 minutes, then remove and let cool.
In a large mixing bowl, beat the cream cheese until smooth and creamy.
Gradually add sugar and vanilla extract, mixing until fully incorporated.
Add the Baileys Irish Cream and melted dark chocolate, mixing until combined.
Add eggs one at a time, mixing well after each addition.
Incorporate sour cream until smooth and creamy.
Pour the filling over the cooled crust and smooth the top with a spatula.
Bake the cheesecake for 55-60 minutes, or until set but slightly jiggly in the center.
Turn off the oven, crack the door, and let the cheesecake cool in the oven for 1 hour.
After an hour, remove the cheesecake from the oven and chill in the fridge for at least 4 hours.
Remove from the springform pan and serve with chocolate shavings if desired.