Prepare the Crust

1. Preheat Oven: Preheat your oven to 325°F (160°C). Grease a 9-inch springform pan and line the base with parchment paper.
2. Make the Crust: In a bowl, mix graham cracker crumbs, sugar, and melted butter until evenly combined.
3. Press into Pan: Firmly press the mixture into the bottom of the prepared pan to form an even crust.
4. Bake: Bake for 10 minutes, then set aside to cool.

Make the Cheesecake Filling

1. Beat Cream Cheese and Sugar: In a large mixing bowl, beat the softened cream cheese and sugar with an electric mixer until smooth and creamy.
2. Add Eggs and Vanilla: Beat in the eggs one at a time, followed by the vanilla extract.
3. Mix in Sour Cream and Melted Toblerone: Gently fold in the sour cream and melted Toblerone until fully incorporated.

Assemble and Bake

1. Pour Filling: Pour the cheesecake filling over the cooled crust, smoothing the top with a spatula.
2. Bake in Water Bath: Place the springform pan in a larger roasting pan. Fill the roasting pan with hot water until it reaches halfway up the sides of the springform pan. This helps prevent cracks.
3. Bake: Bake for 50-60 minutes, or until the edges are set, but the center is slightly jiggly.
4. Cool Gradually: Turn off the oven and leave the cheesecake inside with the door slightly ajar for 1 hour. Then, transfer to a wire rack to cool completely.

Chill and Decorate

1. Chill: Refrigerate the cheesecake for at least 5-6 hours, or overnight, to set.
2. Decorate: Top with chopped Toblerone pieces, whipped cream, and a drizzle of melted chocolate before serving.