For crust, grind nuts in a high-powered blender until they become floury.
Mix ground nuts with coconut oil or butter, egg, and stevia if using, and press into bottom of a pan that will fit in the bottom of your Crock-Pot with a little room on each side. I used a 1 1/2 quart oval CorningWare in my 6 quart oval Crock-Pot and it worked great, though even a bowl or round cake pan or loaf pan could work depending on your Crock-Pot.
Combine all filling ingredients and blend well with blender or immersion blender. Taste to make sure it is sweetened to taste.
Pour over crust in your dish.
Put about 1 cup of water in the bottom of your Crock-Pot.
Slowly and carefully place the dish with the cheesecake into the crock pot, making sure not to get water in it. Put lid on.
Turn Crock-Pot on high and cook about 2 hours. Check every hour or so to make sure there is still water in the bottom.
Cheesecake is done when middle is set and top barely starts to crack.
Turn off heat and leave in crock pot until cooled.
Chill in refrigerator for a few hours before serving.
Melt dark chocolate and drizzle on top of cheesecake before chilling