Roast the peanuts in an oven/toaster oven at 176°C for about 10-15 minutes. Shake the tray in between cooking time so all the sides will get roasted. Once done, remove from oven and let cool slightly.
While the nuts are cooling down, roughly chop the dark chocolate then melt on top of a double boiler over barely simmering water. Remove from heat when the chocolate has evenly melted. Set aside.
In a food processor, grind the peanuts until it turns into a creamy paste.
Add the palm oil, muscovado sugar, milk powder, cocoa powder, salt, and vanilla extract. Blend until added ingredients are mixed well and the sugar is fully dissolved.
Add the dark chocolate and blend until the mixture is loose and spreadable.