Spiderweb Cheesecake

Sprinkle gelatin over water in a small saucepan. Let stand 1 minute. Heat over low heat, stirring until gelatin dissolves. Remove from heat and cool slightly. Beat together cream cheese and sugar in a large bowl until smooth. Gradually beat in cream, vanilla and gelatin mixture. Beat until smooth. Pour over prepared crust. Combine chocolate chips and butter in a small microwave-safe bowl. Microwave until melted. Stir until smooth. Pipe evenly spaced concentric circles about 1/2 inch apart over top of cheesecake. Starting in the middle of cheesecake, pull a toothpick through circles toward edges. Wipe off toothpick and repeat until a spiderweb pattern is formed. Refrigerate 2 hours before serving.