Preheat the oven to 350°F (175 °C) and line an 8"x8" pan with a piece of parchment paper. Note that this crust recipe does not work in a regular pie pan - only as bars.

In a large mixing bowl, mix together the sugar, flour, cocoa powder, and salt. Stir in the melted butter until well combined. If you have difficulties incorporating the butter, use your hands. The mixture will be sticky.

Press the mixture onto the bottom of the prepared pan and bake for 10 minutes. When you remove it from the oven, the crust will still be quite soft but will harden a little as it cools. Let cool for at least 15 minutes while preparing the cheesecake.

Reduce the temperature to 325°F (163 °C).

In a large mixing bowl, beat the cream cheese and sugar until light and fluffy. Add the vanilla, salt and melted white chocolate and beat on low until combined. Add the eggs, one at a time, beating on low after each addition. Do not over mix. Pour evenly over the prepared crust and spread the jam evenly over the top.

Bake for 30 minutes or until the center jiggles just slightly when the pan is tapped.

Let cool completely, about 2 hours, and then refrigerate for at least 2 hours before serving.

Cover and refrigerate for up to 4 days.