Ingredients:
* 15 graham crackers, crushed
* 2 tablespoons butter, melted

* 4 (8 ounce) packages cream cheese
* 1 1/2 cups white sugar
* 3/4 cup milk
* 4 eggs
* 1 cup sour cream
* 1 tablespoon vanilla extract
* 1/4 cup all-purpose flour


Directions:
1. Preheat oven to 350 degrees F (175 degrees C). Grease a 9 inch springform pan.
2. In a medium bowl, mix graham cracker crumbs with melted butter. Press onto bottom of springform pan.
3. In a large bowl, mix cream cheese with sugar until smooth. Blend in milk, and then mix in the eggs one at a time, mixing just enough to incorporate. Mix in sour cream, vanilla and flour until smooth. Pour filling into prepared crust.
4. Bake in preheated oven for 1 hour. Turn the oven off, and let cake cool in oven with the door closed for 5 to 6 hours; this prevents cracking. Chill in refrigerator until serving.

Ingredients:
1 1/2 cups chocolate cookie crumbs
1/3 cup confectioners' sugar
1/3 cup unsweetened cocoa powder
1/4 cup butter

3 (8 ounce) packages cream cheese, softened
1 1/4 cups white sugar
1/4 cup unsweetened cocoa powder
3 tablespoons all-purpose flour
3 eggs
1/2 cup sour cream
1/4 cup Irish cream liqueur

Directions:
1. Preheat oven to 350 degrees F (175 degrees C). In a large bowl, mix together the cookie crumbs, confectioners' sugar and 1/3 cup cocoa. Add melted butter and stir until well mixed. Pat into the bottom of a 9 inch springform pan. Bake in preheated oven for 10 minutes; set aside. Increase oven temperature to 450 degrees F (230 degrees C).
2. In a large bowl, combine cream cheese, white sugar, 1/4 cup cocoa and flour. Beat at medium speed until well blended and smooth. Add eggs one at a time, mixing well after each addition. Blend in the sour cream and Irish cream liqueur; mixing on low speed. Pour filling over baked crust.
3. Bake at 450 degrees F (230 degrees C) for 10 minutes. Reduce oven temperature to 250 degrees F (120 degrees C), and continue baking for 60 minutes.
4. With a knife, loosen cake from rim of pan. Let cool, then remove the rim of pan. Chill before serving. If your cake cracks, a helpful tip is to dampen a spatula and smooth the top, then sprinkle with some chocolate wafer crumbs.