For the crust:
1 cup crushed chocolate cookie wafers
1/4 cup butter, softened
2 tablespoons white sugar
1/4 teaspoon unsweetened cocoa powder
For the cheesecake:
3 (8 ounce) packages cream cheese, softened
1 cup white sugar
1/2 pound semisweet chocolate chips
2 tablespoons heavy cream
1 cup sour cream
1 pinch salt
3/4 cup Guinness® stout beer
2 teaspoons vanilla extract
Preheat oven to 350 degrees F (175 degrees C). Prepare a 9-inch springform pan with butter.
Combine the crushed cookies, butter, 2 tablespoons sugar, and cocoa in a small bowl; mix; press into the bottom of the springform pan.
Place the cream cheese in a large bowl and beat with an electric mixer set to low speed until smooth. While beating, slowly add 1 cup sugar and then the eggs, one at a time. Continue beating until smooth.
Combine the chocolate chips and heavy cream in a microwave-safe dish. Heat in the microwave until the chocolate is completely melted, stirring every 30 seconds. Beat the chocolate into the cream cheese mixture. Add the sour cream, salt, beer, and vanilla; blend until smooth.
Pour the mixture over the crust. Place the pan into a large, deep baking dish. Fill the dish with water to cover the bottom half of the springform pan.
Bake the cheesecake in the water bath in the preheated oven for 45 minutes; turn oven off; leave the cheesecake in the oven with oven door slightly ajar another 45 minutes; remove from oven. Run a knife along the edge of the cheesecake to loosen from pan. Chill in refrigerator at least 4 hours.