Line a nine-inch springform pan with parchment paper. Wrap the exterior of the pan with heavy duty foil and place into a slow cooker bag to prevent water seeping inside.

Combine crust ingredients and press into the bottom of springform. Freeze for 15 minutes while preparing cheesecake batter.

Preheat oven to 325 degrees Fahrenheit. In the bowl of a mixer, beat cream cheese and sugar until smooth. Add sour cream and mix gently. Add eggs one at a time, mixing for a moment in between. Do not overmix. 

Divide the batter into two bowls. In one bowl, fold in the liquor and Nocillato D. In the second bowl, fold in the vanilla bean paste or extract. Starting with the chocolate mixture first, pour a cup of batter into the center of the crust. Top with the vanilla batter, pouring it into the center of the chocolate batter. Alternate colors until all the batter is used up. Tap pan gently on the counter to settle the layers.

Set the wrapped pan into a large roaster pan and place in the oven. Pour hot water into the roaster pan until halfway up. Bake for one hour and 15 minutes, until the outer edges are set and the center is still wobbly. Turn off the oven and leave the cheesecake to cool in the oven. Refrigerate before removing sides of springform pan.

Place chopped chocolate in a heat-safe bowl. In a small saucepan, heat cream over low flame until just barely simmering. Pour the cream over chopped chocolate. Let stand one minute to melt chocolate. Whisk to combine. Place in refrigerator to chill.

Using the whisk attachment, beat until fluffy. Transfer to piping bag fitted with start tip. Pipe rosettes around cheesecake and sprinkle with Chopped Viennese Crunch.