Peel 2 shallots, cut into small cubes, and mix with the soft butter, mustard, 1 tablespoon flour, 1 tablespoon capers, and 2 tablespoons chopped herbs (dill, parsley, tarragon) until well combined.
Rinse the 4 cod fillets (150 g each) under cold running water, pat dry, and season generously with salt and pepper.
Peel the 8 jacket potatoes, cut into slices, and arrange in a greased baking dish. Season with salt and pepper and drizzle with 5 tablespoons of white wine.
Place the seasoned cod fillets on top of the potatoes and spread the shallot-butter mixture evenly over each fillet.
Roughly crumble the 60 g of potato chips and scatter over the fish and potatoes.
Bake in a preheated 180°C (350°F) oven for 25 minutes until the fish is opaque and flakes easily, and the chip topping is golden and crispy.