Place the heavy cream into a saucepan over low heat.
Add the vanillia bean (or vanilla extract) to the cream and allow to infuse for 5 minutes.
Turn off the heat and set aside to cool.
In a mixing bowl, add the egg yolks and sweetener and whisk until the mixture is pale. Add caramel flavor if desired.
Check the temperature of the cream, if the cream is cool enough for you to put your finger in it then it is ready to use. *If not allow to sit for a little longer to cool.
Pour ¼ of the cream mixture into the egg yolk and whisk to combine, add another ¼ of the cream and finally all of the cream. This method is called tempering and allows the eggs to slowly warm up without cooking.
Pour the eggs and cream back into the saucepan and back over low heat.
Using a silicone spatula, continually stir the mixture until it begins to thicken. The mixture is thick enough when it coats the spatula without dripping off.
Pour the custard into a clean mixing bowl and continue to stir as it cools for 5 minutes. Add your chopped macadamia nuts. To cool quicker, place the bowl of pudding into larger bowl filled with ice cubes.
Place a sheet of cling film over the custard and press it onto the surface to prevent a skin from forming.
Place the custard in the fridge for 1-2 hours(we recommend at minimum 2 hours) to cool completely before completing assembly.
Add chilled custard layer to pie shell, and gently spread out filling your pie.