Clean and wash the cabbage and remove 4 large leaves. Blanch in boiling salt water. Take out, drain. Cut leaves in half. Cut thick leaf veins flatter. Cut remaining cabbage into strips.
Fish fillets wash, dry dab, crosswise halve and spice. Cover each fillet with 1⁄2 cabbage leaf and spread with 1⁄2 TL Pesto. Roll up the fillets and pin them.
Wash the thyme. Bring the stock, wine and possibly Pernod to the boil in a deep pan (with lid). Add thyme, 1⁄2 tsp. salt and a little pepper. Cover the rolls and cook them at low heat for about 10 minutes.
Peel and chop the onion and sauté in hot butter. Steam cabbage briefly. Add 5 tablespoons of water, cover and stew for about 10 minutes. Season to taste.
Lift out the rolls, keep warm. Sieve the stock, boil down. Stir in crème fraiche and the rest of the pesto. Season to taste. Potatoes taste good with it.