Here's how I do it.
Take your tenderloin cut (fillet in UK) and cut it DOWN, not across the grain, into as many pieces as you like.
Sear these pieces very quickly.
Now slice the pieces across the grain as thinly as you like.
Finally - and this is how to do it - flatten each slice with a pallet knife, leaning down from the center out. This will make fantastic circular slices of the beef, and will get them tissue-paper thin.
Be careful to transfer each slice onto a cold plate, otherwise it will fall apart.
Take your tenderloin cut (fillet in UK) and cut it DOWN, not across the grain, into as many pieces as you like.
Sear these pieces very quickly.
Now slice the pieces across the grain as thinly as you like.
Finally - and this is how to do it - flatten each slice with a pallet knife, leaning down from the center out. This will make fantastic circular slices of the beef, and will get them tissue-paper thin.
Be careful to transfer each slice onto a cold plate, otherwise it will fall apart.