Butterfly each chicken breast and flatten between clingfilm using a rolling pin.
Mix butter, parsley, garlic, spring onions, and cheese, then shape into four sausages.
Prepare separate bowls for beaten eggs, flour, and breadcrumbs.
Peel cucumbers into ribbons and mix with spring onions, soured cream, mayonnaise, and paprika.
Garnish the salad with sliced hard-boiled eggs and set aside.
Season chicken, roll tightly around the butter stuffing, and coat sequentially in flour, egg, and breadcrumbs.
Heat oil in a frying pan or deep-fat fryer to 160°C.
Fry chicken for 15 minutes until golden and juices run clear.
Drain chicken on kitchen paper and serve with the cucumber salad.