Preheat the oven to 200°C.
Place duck skin-side down in a non-stick ovenproof pan and fry over medium heat while draining excess fat.
Turn the duck over once the fat has rendered and cook for 3 minutes until golden-brown.
Transfer the pan to the oven and roast for 10 minutes.
Heat butter, sugar, chilli, and red wine in a pan and bring to a boil.
Add plum pieces to the reduced wine and cook for 3 minutes until softened.
Stir in the cornflour mixture to thicken and season with salt and pepper.
Crush the cooked potatoes in a bowl with olive oil, salt, and pepper.
Fold in the crushed peanuts and chopped dill.
Serve the duck with the crushed potatoes and a drizzle of plum sauce.