Raspberry Sauce: Stir together the raspberries, sugar, cornstarch and water in a medium saucepan. Bring to a boil, stirring occasionally, then boil for 5 minutes. Pour through a fine mesh strainer to catch the seeds. Store sauce in the refrigerator until you make the cheesecake.

Crust: Preheat oven to 350 degrees. Stir the crushed Oreos and melted butter together and press into the bottom of a springform pan. Bake for 10-15 minutes, until the crust is set. Remove and cool. Reduce the oven temperature to 325 degrees.

Filling: In a medium saucepan, heat the half and half until it is almost simmering. Remove from heat and stir in the white chocolate pieces until smooth and melted. Set aside. In a big bowl, beat together the cream cheese and sugar until smooth. Beat in the eggs, one at a time, make sure to blend completely after each one. Beat in the vanilla, salt and melted white chocolate mixture.

Baking the Cheesecake/Water Bath: Wrap your spring form pan containing the crust tightly in foil. Place the foil-wrapped pan in a roasting pan, and put a pot of water to boil on the stove for the water bath you will be making.

Pour half of the filling over the crust, sprinkle with the chopped Hershey bars. Drizzle about 5 Tablespoons of raspberry sauce over the filling and chocolate and swirl with the tip of a knife. Pour the rest of the filling on top, drizzle with another 5 Tablespoons of sauce, and swirl again with the knife.

Pour boiling water into the roasting pan to surround the spring form pan. Fill until the water reaches about halfway up the pan. Bake the cheesecake at 325 degrees for 60-70 minutes, until the center is almost set. (it will still jiggle if you shake the pan)

Remove the roasting pan from the oven, letting the cheesecake sit in the hot water for another 30 minutes. Remove the spring form pan from the water onto a cooling rack to cool to room temperature—place in the refrigerator for 3+ hours to cool completely.

Make the ganache: In a saucepan, bring the heavy cream just to a boil. Remove from the heat and stir in the chocolate until smooth. Pour the ganache over the top of the cooled cheesecake, smoothing with a spoon and allowing some of the ganache to drip over the sides of the cheesecake. Return to fridge to chill another 3 hours, or until ganache is shiny and set.