Let’s assume you can stack the apples, and passing through both is still 1 stroke. That means cutting through 10 could still be considered 1 stroke.

Stack the apples.

Cut entirely through the top one directly in half.

Continue cutting through the second one.

As you cut through it, one of the people takes the top apple, rotates it 60 degrees, and puts it under the bottom apple.

Finish cutting through the now top apple and continue cutting through the now bottom apple (the original top that was already in half).

Repeat this until you’ve cut each into 6 pieces like this (picture not mathematically accurate, for visual purposes only).

Give everyone 4 each.