Fry the finely chopped onion in a little oil. Add the mushrooms, carrots and zucchini, season with a little salt and pepper and sauté for about 5 minutes. Put in a colander and drain well.
Whisk the egg yolks with milk, garlic, Parmesan and a level teaspoon of salt. Add the flour and stir in well. Beat the egg white until stiff and carefully fold in with the vegetables.
Heat some oil in a pan. Pour in the batter and bake on the stove over medium heat until golden. Divide into 4 parts with a spatula. Turn the parts and bake on the other side until golden. Then cut into bite-sized pieces.
For the garlic dip, mix the sour cream, yoghurt, garlic and dill together well and season with a little salt.
Serve the vegetable pancakes with the garlic dip and salad.