Wrap 2 layers of foil around the outside of a 10″ springform pan making sure to cover the bottom and sides.
If you aren’t using a non-stick pan, spray pan liberally with cooking spray.
Preheat oven to 300º.
Use an electric mixer with the paddle attachment, combine cream cheese & butter & beat until smooth.
Add eggs one at a time until blended.
Beat in sour cream.
Add sugar & cornstarch & beat until very smooth.
Fold in the fresh raspberries.
Pour into prepared chilled pan.
Top with raspberry jam & then drag a knife or chopstick through the jam to give the marbelized look. Don’t over-mix.
Place in a large roasting pan.
Place pan in preheated oven & carefully pour boiling water into roasting pan to fill halfway up sides of the cheesecake pan.
Bake 2 – 2.5 hours, or until cake is lightly browned on top.
Remove from water bath & foil & cool at room temperature for at least 2 hours.
Cover & refrigerate overnight to bring it to ideal cheesecake temperature.
When ready to serve, top with whipped cream & more fresh raspberries.