Peel and wash the potatoes and cook them in boiling salted water for about 20 minutes. Wash chicken breasts, dab dry and remove 2 fillets from the bone each. Drain the potatoes and swivel them dry on the still hot cooking place.
Press through a potato ricer. Stir in 2 egg yolks, 3 tablespoons of milk and butter. Season to taste with salt, pepper and nutmeg. Pour into a piping bag with a large star-shaped spout and squirt about 16 duchess potatoes onto a baking tray lined with baking paper.
Whisk 1 egg yolk with 2 tablespoons of milk and carefully brush the potatoes with it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 15 minutes. Heat 2 tablespoons of oil in a pan.
Season chicken fillets with salt and pepper, fry for 6-8 minutes on each side. Remove the chicken fillets and keep warm. Add red wine, crème de cassis and redcurrant jelly to the roast mixture and let it boil down for about 5 minutes at low heat until it is creamy.
Wash the currants, put 4 panicles aside for garnishing. Pluck the remaining currants from the panicles. Add crème fraîche and currants to the sauce. Arrange chicken fillets, duchess potatoes and cassis sauce on preheated plates, garnish with currant panicles and thyme twigs.