Whisk the coffee, cream and instant coffee together in a saucepan over medium low heat until simmering, but do not boil.
In a bowl stir together the egg yolks, sweetener, stevia and salt.
Pour a small amount of the cream mixture into the egg mixture to temper it then gradually add the remaining egg mixture into the sauce pan on the stove.
Bring this to a boil, reduce to simmer, constantly stirring until mixture thickens and coats the back of the spoon, 175 degrees F.
Once thickened, pour into a clean bowl and allow to cool for 30 minutes.
Cover and place in the refrigerator for 2-3 hours.
Once cooled, stir in vodka if using, then pour this into an ice cream machine and follow manufacturers instructions.
I used my KitchenAid ice cream attachment and it took about 20 minutes for the texture of soft serve ice cream.
When done, remove to a bowl and stir in chocolate and coffee beans. Pour into a container of choice and freeze for 3 hours or over night.
Allow to sit on counter to soften for about an hour before serving.