Wring out the lemon. Rinse the fish fillets, rub dry and cut into 3 cm pieces. Sprinkle with the juice of one lemon and season with salt and pepper.
Rinse the chives, shake dry and cut into rolls.
Heat a little butter in a frying pan, sauté the fish for about 2 min, then remove from the pan.
Melt a little additional butter in the frying pan, stir a little flour to make a roux, extinguish with the vegetable soup as well as the wine. Simmer while stirring.
Fold in the crème fraîche and mustard and season the sauce with salt and freshly ground pepper.
Add the fish pieces to the sauce and simmer for about 5 minutes.
Arrange the ragout on plates and sprinkle with chives.
Tip: Serve with long-grain rice, boiled or fried potatoes.