Divide the cheesecake batter evenly among the 12 muffin cups, filling each cup about 2/3 - 3/4 of the way full.
Then, spoon about 2 tsp of Nutella into each cheesecake cup. Using a cake tester, toothpick, or knife, swirl the Nutella into the cream cheese mixture.
Bake for about 16-20 minutes, or until the edges of each cheesecake have set and the centers of each jiggle slightly when the pan is gently shaken.
Then, turn off the oven, crack open the oven door, and let the cheesecakes slowly cool in the oven for 30-45 minutes (this helps prevent each cheesecake from cracking).
Next, continue to let the cheesecakes cool to room temperature on the counter.
Finally, chill in the fridge at least 4 hours, or overnight.
Serve plain or topped with whipped cream, fresh raspberries, and shaved chocolate.
Keep leftovers in an airtight container in the refrigerator.