Wash the potatoes and cook covered in water for about 20 minutes. Quench, drain and remove the skin. Leave to cool. In the meantime, boil the eggs in boiling water for about 10 minutes until hard. Quench, peel and let cool.
Peel the carrots, halve them lengthwise and cut into slices. Cover and simmer in little boiling salted water for 5 minutes. Add the frozen peas for the last 2 minutes. Drain the vegetables.
Cut the potatoes into small cubes. Cut 1 egg into eighths, dice the rest finely. Halve cucumbers lengthwise and cut into thin slices. Clean, wash and spin-dry lettuce and cut into strips, except for 4 leaves.
For the sauce, mix salad cream, sour cream and cucumber water. Season to taste with salt, pepper, vinegar and 1/2-1 teaspoon sugar. Mix all salad ingredients with the sauce. Let the Russian salad stand for at least 1 hour.
Season again with salt and pepper. Serve on the salad leaves with the egg quails.