1. For topping, place chocolate chip cookies and white Viennese crunch in a large ziplock bag. Crush into small pieces. Set aside.
2. Prepare the chocolate ice cream: Beat the pareve whipping cream on high speed until peaks begin to form. Add the eggs one at a time. Slowly add the sugar, dissolved coffee granules, vanilla sugar, cocoa, and chocolate syrup and mix until smooth.
3. Line a cookie sheet with silver foil. Sprinkle half of the crunch mixture onto the cookie sheet. Spread chocolate ice cream on top. Top with remaining crunch mixture. Freeze until firm.
4. When chocolate ice cream is frozen, prepare the vanilla ice cream: Beat the pareve whipping cream on high speed until soft peaks begin to form. Add in the eggs, mixing thoroughly in between each one. Add in the sugar and vanilla sugar. Mix until stiff peaks form.
5. Spread vanilla ice cream over the chocolate ice cream, leaving a two-inch strip along the length of the cookie sheet that is only a chocolate layer.
6. Freeze until the ice cream firms slightly. (If it is too firm, it will crack when you roll it.) Roll up lengthwise, beginning with the chocolate side. Freeze completely.