Preheat oven to 350 degrees F (175 degrees C).

Butter a 9-inch springform pan.

Combine crushed chocolate cookie wafers, softened butter, 2 tablespoons sugar, and cocoa powder in a small bowl.

Mix well.

Press the mixture into the bottom of the springform pan to form the crust.

In a large bowl, beat softened cream cheese with an electric mixer on low speed until smooth.

Slowly add 1 cup of sugar while beating.

Add the eggs one at a time, continuing to beat until smooth.

Combine chocolate chips and heavy cream in a microwave-safe dish.

Heat in the microwave in 30-second intervals, stirring each time, until the chocolate is completely melted.

Beat the melted chocolate mixture into the cream cheese mixture.

Add sour cream, salt, Guinness stout beer, and vanilla extract.

Blend until smooth.

Pour the cheesecake mixture over the prepared crust.

Place the springform pan into a large, deep baking dish.

Fill the baking dish with water to cover the bottom half of the springform pan (water bath).

Bake in the preheated oven for 45 minutes.

Turn off the oven and leave the cheesecake inside with the oven door slightly ajar for another 45 minutes.

Remove the cheesecake from the oven and water bath.

Run a knife along the edge of the cheesecake to loosen it from the pan.

Chill in the refrigerator for at least 4 hours before serving.