I find this works best using silicone cupcake cases, as this makes it easy to remove the chocolate cups. So I like to lay these out in a container before I begin.
Gently melt the coconut oil in a saucepan over a low heat until liquid.
Stir through the cacao powder, salt and sweetener of choice until everything is all melted together and you're left with a smooth, melted chocolate like consistency.
Pour a little of the chocolate mixture into the base of some silicone cupcake cases and pop these into the freezer for around 10 minutes to set.
In a separate bowl, mix together the peanut butter and sweetener until well combined.
Add a small spoon of the peanut butter mixture into each of the cups and cover these with the rest of the chocolate.
Place them back into the freezer and leave for 1-2 hours to allow the chocolate to set completely.
Carefully remove the cups from their cases and drizzle with a little extra melted dark chocolate to decorate.