In a small bowl, mash and stir the butter, Worcestershire, mustard, curry powder and ½ teaspoon pepper until well combined; set aside.
Season the steak(s) with salt and pepper. Cook using your preferred method to the desired degree of doneness. Transfer to the center of a large cutting board, then immediately dollop with the butter mixture. Let rest for 10 minutes.
Thinly slice the steak (against the grain if using a cut such as flank with striated muscle fibers). Toss the slices with the sauce to mix in any accumulated juices. Taste and season with salt and pepper. Serve directly from the board.
