Cover the sieve with a linen cloth and leave for 30 seconds. place in a pot of boiling water. Remove the sieve, put yogurt in it, cover with a film and leave overnight.
Peel cucumber, cut in half, remove seeds. Grate, mix with salt and leave for 3 hours. Squeeze out the released juice from the present cucumber.
Transfer the yogurt to a bowl, add sour cream, lemon juice, chopped garlic, cucumber, dry dill and parsley. Stir and refrigerate for at least 2 hours.