Cook asparagus and pepper strips in a skillet with just a bit of water, covering to steam for about 4 minutes. Drain and return to heat to dry pan. Add butter and cook with butter bubbling to coat the vegetables, seasoning all over with salt and pepper to taste. Set aside.

Tenderize each steak by either piercing all over numerous times on both sides with a fork or by pounding on just one side with a meat mallet or heavy frypan.

Season top side of each steak with salt and pepper. Spread each with mustard and cheese. Add 3 asparagus spears and pepper strips to each and sprinkle each with nuts if desired. Roll up like jelly roll and tie with each with 2 to 3 pieces of butcher twine. Season each bundle (involtini) all over with salt and pepper.

Pan-sear in well-oiled hot cast iron or nonstick pan until browned all over. Reduce heat to medium and continue to cook, covered, turning each often until cooked to about 140°F inside for medium-rare when tested with a digital instant read thermometer. Let stand for 5 minutes before serving.