This cinnamon buttermilk cheesecake is not too sweet. Feel free to up the amount of granulated or brown sugar by an ounce or so. The critical ratio is egg to cream cheese and other liquid, so it's okay to play with the amount of sugar some.
Set your oven rack to the middle setting and preheat your oven to 350F.
Whir up the biscotti in the food processor until you have fine crumbs.
Add the rest of the ingredients and pulse until evenly blended.
Pat evenly on the bottom and partway up the sides of a 9" springform pan. I find it easiest to use a glass for this.
Bake for 10 minutes.
Remove from oven and set aside.
For the Cheesecake
Reduce the oven temperature to 325F.
On low speed in your stand mixer, mix the cream cheese until smooth.
Ad the cinnamon, vanilla, salt and nutmeg and mix on low until evenly blended, scraping the bowl as necessary.
Slowly add in the sugars, keeping the mixer on low speed and scraping the bowl as necessary.
Drizzle in the eggs, a bit at a time, until they are all incorporated.
Continue mixing on low speed, scraping the bowl as necessary.
Slowly stream in the buttermilk, mixing until well combined. Scrape the bowl as necessary.
Pour the batter into the pan, rapping it on the counter a couple of times to dislodge any air bubbles. Pop any bubbles that rise to the surface.
Bake for an hour, or until just the center of the cake is a bit jiggly.
Carefully and evenly spread on the apple pie jam. (See Notes for other ideas for toppings)
Turn off the oven but leave the cheesecake in for another 30 minutes.
Crack the oven door and leave the cheesecake in the oven for another 30 minutes.
Remove the cheesecake from the oven and let cool to room temperature.
Chill for four hours or overnight before slicing and serving. (Run a thin-bladed knife or icing spatula around the inside of the springform pan to loosen it before removing the sides to slice).
The cake will be more flavorful if you let it sit out for about thirty minutes after slicing but before serving.
Store leftover cake in the refrigerator, covered, for up to four days.
Notes
If you can't find apple pie jam, feel free to top with your favorite cooked apple pie filling. You could even top it with cinnamon apple sauce or apple butter if you wanted, as well.