Preheat the oven to 180°C/fan 160°C/gas mark 4. Once hot, roast the peanuts for both layers for 10-12 minutes until golden. Leave to cool.
Place the peanuts for the caramel layer in a food processor and blitz until it resembles fine breadcrumbs. Add the medjool dates and the maple syrup and blend again until a dough is formed.
Place a small teaspoonful of the mixture in your hand and flatten out. Place a peanut in the middle and bring the sides up to cover it, then roll into a small ball and lay on a tray. Repeat with the remaining mixture until you have 25 balls. Leave in the fridge to firm up for 15 minutes.
Blitz the peanuts for the chocolate layer until they resemble fine breadcrumbs, then add the dates, cocoa powder and maple syrup until it comes together. Place a generous teaspoon of the mixture in your hand and flatten, then place one of the caramel balls in the middle and work the mixture around them. Roll again to make a ball and place back in the fridge to firm up for another 15 minutes.
Meanwhile, melt the dark chocolate in a heatproof bowl over a pan of simmering water, stirring regularly until completely melted. Leave aside to cool for around 5 minutes. Line a large tray with greaseproof paper.
Dip the balls into the chocolate until completely coated, then place on the lined tray. Return to the fridge for around 1 hour until completely firmed up.