Combine butter and crumbs, mixing well with a fork. Press into the bottom of a 10-inch springform pan.
For the caramel:
Combine sugar and water in a saucepan over medium-high heat. Add zest and stir well. Cover with a lid and cook until sugar turns a medium amber color, about 3-6 minutes after mixture comes to a boil. Remove from heat and stir 30 seconds. Slowly stir in cream, being careful to avoid spatters. Set aside.
For the cheesecake:
Beat cream cheese and both sugars at medium speed with an electric mixer until soft and fluffy. Add vanilla and salt. Add eggs one at a time, beating on lowest speed of mixer just until incorporated.
Pour two-thirds of batter over crust. remove zest from caramel and beat caramel mixture into remaining batter. Pour caramel batter over plain batter in pan and swirl mixtures with a rubber spatula.
Place in center of the oven and bake for about 50 minutes, or until edges are firm but middle still Wiggles. Remove from oven and cool. Chill.
Beat the 1 cup whipping cream till stiff and spraed on chilled cake.
Combine sugar and water in a saucepan. Cover and bring to a boil. Boil until mixture is light brown and a small amount dropped in cold water forms a brittle ball. Remove from heat and immediately pour into 2 9-inch circles, on a well-buttered cookie sheet pan.
When the caramel starts to harden, cut each circle into six wedges a sharp knife. As caramel continues to harden, recut the wedges several times.
Slide the tip of a sharp knife under a wedge and remove from plate.
Place on a buttered cookie sheet to continue cooling. Continue with remaining panes. Some may break. Save six of the most attractive panes for the decoration.
Just before serving, placing panes vertically into the cheesecake.