Wash and brush the potatoes thoroughly. Cook in plenty of boiling salted water for 15-20 minutes. Wash and peel asparagus and cut into bite-sized pieces. Cook in boiling salted water for 8-10 minutes.
Carefully wash the dill, dab dry and cut finely. Mix vinegar, stock, salt and pepper. Whip the oil into it. Stir in dill and frozen onion-garlic mixture. Drain potatoes, rinse with cold water and cut lengthwise into thin slices.
Add lukewarm potato wedges and drained asparagus pieces to the vinaigrette and marinate for about 30 minutes. In the meantime, clean, wash and drain the rocket and rocket salad. Cut into bite-sized strips except for a few leaves for garnishing.
Wash and halve the tomatoes. Clean the mushrooms and cut into thin slices. Add lettuce, tomatoes and mushrooms to the potatoes. Line a bowl with some romaine lettuce leaves and place the salad on top.