Clean the Brussels sprouts, wash them, possibly halve them. Peel and chop the onions. Wash and chop the thyme. Cook the sprouts in boiling salted water for about 20 minutes. Meanwhile portion, wash and dry the fillet.
Turn in flour, whisked egg and breadcrumbs one after the other. Fry in hot oil on each side until golden brown. Season with salt and lemon juice. Fry over medium heat for about 10 minutes. Drain the Brussels sprouts. Melt the fat. Sauté onions in it. Add sprouts, cream and thyme. Reduce at high heat for 2-3 minutes. Season to taste again.
Melt the fat. Sauté onions in it. Add sprouts, cream and thyme. Reduce at high heat for 2-3 minutes. Season to taste again. Serve fish and vegetables garnished with herb bouquets and lemon. Boiled potatoes taste good with it