Preheat oven to 325°F (163°C). In a medium bowl, mix graham cracker crumbs, 0.25 cups sugar, and melted butter until well combined. Press mixture firmly into the bottom of a 9-inch springform pan.
In a large bowl, beat cream cheese and 1 cup sugar until smooth and creamy.
Add eggs one at a time, beating well after each addition.
Mix in Baileys Irish Cream, vanilla extract, and sour cream until fully incorporated.
Pour the cheesecake batter over the crust in the springform pan.
Bake for 45 minutes until the edges are set but the center is slightly jiggly.
Turn off the oven and leave the cheesecake inside for 1 hour to cool gradually.
Refrigerate for at least 4 hours or overnight before serving.
Notes
For an added touch, garnish with whipped cream and chocolate shavings before serving.