The False Shuffle

— it retains a card at the top of the pack, although you apparently mix all the cards thoroughly.

Hold the pack in the normal shuffling position – thumb on face card, fingers on back card.  Press with fingers on back card.

Right hand draws out a portion of cards, but left hand fingers retain the back card (shown shaded).

Right hand drops its cards in front of those retained in left hand.  The left hand fingers, pressing against back card, always keep it in the same place.