Wash and peel the asparagus and cut off the woody ends. Wash the fish, dab dry and cut into 3 pieces. Cut the skin slightly with a sharp knife. Sprinkle with lemon juice and salt.
Put the asparagus in boiling salted water with 1 teaspoon sugar, bring to the boil and cook for 12-16 minutes. Clean the rocket, wash and drain well. Peel, wash and clean the carrots. Cut carrots into thin strips with the potato peeler.
Cut the vanilla pod in half lengthwise, scrape out the pulp with the back of a knife. Put butter, pepper berries and vanilla pulp in a small pot, melt butter. Meanwhile heat 2 tablespoons of oil in 2 pans and fry the fish pieces in them on the skin side for about 3 minutes.
Turn the fish pieces, remove the pan from the heat and keep it warm. Mix rocket, carrots, vinegar and 1 tbsp. oil in a bowl and season with salt, pepper and a little sugar. Remove the asparagus from the water.
Arrange asparagus, fish and salad. Pour butter over the asparagus.