Cut the beef into half inch slices. Make sure to remove any sinews. Cut each slice into strips about two inches long.
Place the beef in a bowl. Add the salt, pepper and garlic. Mix well. Cover and marinate in the fridge for at least an hour.
Heat a heavy frying pan (a pan with a thin bottom will not do for this cooking method). Drop in the butter, lift the pan and swirl to melt the butter without burning.
Set the pan on the stove and, working fast, spread the beef strips on the bottom of the pan. Sear over high heat without disturbing for a minute and a half or until the undersides are browned.
Flip the pieces over, sear for a minute then stir. Cook for a minute longer, stirring occasionally.
Scoop out the beef, transfer to a plate and cover loosely.