In a bowl, mix cream cheese, sugar, vanilla extract, yolks, and cornstarch. Use a hand blender to blend until smooth. Add vanilla ice cream and blend until combined.

Remove 3/4 cup of the mixture and set aside.

Fill log mold with the mixture until approximately 1/4 inch from the top and freeze for 20 minutes.

Melt two thirds of a chocolate bar and add to the mixture that was set aside. Pour this into the log mold, creating a line down the center. Freeze for 10 minutes.

Melt remaining chocolate together with the butter. Remove log from the freezer. Add a thin layer of crushed cookies on the top and then pour the melted chocolate over it evenly.

Keep in the freezer until serving.

Heat sugar and water in a small saucepan over medium heat. Brush the sides of the pot with a pastry brush and water from time to time to prevent crystalizing. Cook until desired color is reached and then close the flame.

Stick hazelnuts onto a skewer and dip into the caramelized sugar. Suspend skewer on the edge of a pan, letting the caramel drip down, forming a strand. Let cool and then break the strand to desired height.