Preheat oven to 325 degrees F.
Make sure springform pans have bottoms properly positioned (I like to have the lip edge face down for these minis) and spray the inside of pans with cooking oil spray.
In a small bowl, mix together crust ingredients: graham cracker, butter & sugar
Once mixed thoroughly to wet sand-like consistency, divide evenly among the 3 pans and use a flat bottom glass (a pint glass would do) to press down and flatten the crust real tight up against the springform bottom.
Bake in the oven 8 minutes or until lightly golden.
Let the pans cool to the touch on a cooling rack.
While they're cooling you can start mixing together your cheesecake mixture. You can use a stand mixer, but you can honestly do it all with a hand mixer (My personal preference).
Add cream cheese, Nutella, sugar, salt and vanilla to medium size mixing bowl and mix well with hand or stand mixer.
Then mix in sour cream and egg, mix well till there are no clumps or white spots.
If your pans are cool enough to handle and crust is cool to touch you can go ahead and add your filling to the pans, evenly dividing among the 3 pans.
Tap each pan on the counter for about 30 seconds, just to make sure there are no air bubbles. Important Note: I highly recommend lining the bottom of your oven with a large piece of foil or placing the pans on a baking sheet as they can leak liquid that will smoke in your oven. This wouldn't happen if they were in a water bath, but these are not. (I learned this the hard way =)
Bake the cheesecake mini for 30 minutes or until the center is just slightly jiggly.
Turn oven off, crack open the oven door and allow pans to start cooling slowly to help keep cakes from cracking. 15 minutes with the door cracked open, then 15 on a cooling rack on the kitchen counter, then transfer to the refrigerator to cool for another 1 hour.
Optional
This last step is optional, but highly recommended! Make a beautiful chocolate ganache for your minis.
NOTEIf you do not want to make drips and you just want a thicker layer of chocolate on top of your cheesecake, add a Tablespoon at a time of your cream till you get the consistency you're looking for. Make a double boiler by boiling about an inch of water in a small pot and then a bowl on top for the steam to melt your chocolate.
Once the pot is boiling, Add the chocolate, half & half and butter to a your double boiler pot and once the chocolate just starts melting, stir it all until the chocolate is a smooth, shiny consistency.
Wait 10 minutes and then start dripping along the edge of the cheesecake, then swirl some on top and smooth it out. You can use just a spoon for this or a squeeze bottle, whatever works best for you.
Chill in the fridge till you are ready to serve it.