For the batter: mix the flour and salt and make a hollow in the middle. Stir together the milk, eggs and water and pour into the hollow. Stir into a smooth batter. Cover and allow to stand for 30 mins. at room temperature, then mix in the butter.
Without any additional fat, and using a non-stick pan, fry 8 pancakes from the batter.
For the salad: stir together the quark, cheese, mustard, vinegar and oil. Season. Mix the kohlrabi, radishes and spring onion in with half of the sauce.
Spread the remainder of the sauce on the pancakes and cover with lollo lettuce. Spread the kohlrabi mixture on top. Shape the pancakes into a cornet and serve immediately on plates.