Dice 125 g butter. Mix 100 ml water and sauce powder in a saucepan, bring to the boil. Add butter. Season sauce with horseradish.
Wash the cress and cut from the bed. Wash the plaice fillets, dab dry and season with lemon juice and salt. Halve the salmon slices, place them on the plaice fillets and sprinkle with half of the cress.
Roll up the fillets and pin them down.
Place the rolls in a greased casserole dish and spread horseradish sauce over them. Bake in a preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer) for approx. 20 minutes.
Peel, wash and slice the carrots. Sauté in 2 tablespoons of hot butter. Season with salt and 1 tsp. sugar. Add 1⁄8 l water, cover and steam for about 8 minutes. Arrange everything. Sprinkle plaice rolls and carrots with remaining cress.
Bread or potatoes taste good with it.