Preheat oven to 375. Line 8×8 baking dish with foil (to ensure easy removal of bars), and spray foil with non-stick cooking spray.
Remove graham cracker crust from pre-made pan, and crumble/press it down, re-forming it into your foil-lined pan. Put crust into the oven to bake for 8 minutes, then remove from oven.
Meanwhile, when crust is baking, cream together all of the ingredients, (except for the strawberry jam and blueberries), with a hand held mixer until smooth.
Pour filling over graham cracker crust, smoothing out filling with a spatula.
Drop jelly (by the spoon-full) over cheesecake filling. Drag a spoon (or knife) gently through filling to create marbling. Drop blueberries evenly over cheesecake. Place in the oven, bake for 30-35 minutes, or until cheesecake is almost set in the center. Let cool, and chill in the refrigerator for a few hours, or overnight.
After chilled, remove from the refrigerator, and pull entire cheesecake out of pan. Use foil to lift cheesecake out of pan and onto a cutting board. Cut bars into 12 even bars, (I used a pizza cutter and wiped the blade clean with a paper towel between each cut). Refrigerate until ready to serve.
Enjoy! Store in an airtight container in the refrigerator.