Preheat the oven to 340F / 190C / 170 fan.
Add the butter and sweetener to a small non-stick pan. Melt over a medium heat.
Fill a small bowl with ice and cold water.
Cook for 5 minutes to thicken then add the cream. Cook for a further 5 - 6 minutes on a low heat until you get a nice caramel. Add salt, vanilla and cinnamon (off the heat) then whisk with a until smooth.
Place the hot pan with caramel over the bowl filled with iced water (this will stop the caramel cooking further). Allow to cool for about 3 minutes. Stir the chopped pecans through caramel sauce.
Once the caramel is cool (it can still be a little warm but shouldn’t be hot to stop the egg splitting) add the egg and whisk again until smooth.
Add caramel filling to the pie crust. Decorate top with whole pecans.
Cook for 35 - 45 minutes until golden brown. If the crust starts to brown too quickly after about 20 mins you can loosely cover with a sheet of aluminum foil. Allow to cool before slicing. Serve with cream or sugar free whipped cream.
Storage: Cover with plastic wrap or store in an airtight container for 4 days or freezer for 2 months