Place all the ingredients except roasted peanuts into a food processor. Process for 1 minute.
Add roasted peanuts and process at the lowest speed for 30 seconds.
Press the mixture into your tin and leave it in a freezer for at least 2 hours to firm up.
Once the bars are firm, remove them carefully from the tin. Heat dark chocolate in a heatproof bowl over the saucepan with boiling water. Cover the bars with melted chocolate according to your liking. Sprinkle the bars with roasted chopped peanuts.