Whisk together barbecue sauce, seasoned butter, jalapeño (if using), lime zest and juice, garlic, and ½ tsp (2 mL) of the salt in large bowl. Scrape mixture into large re-sealable plastic bag. Add steaks to bag, rubbing to coat steaks completely. Place bag in bowl (to guard against leaks) and refrigerate at least 30 min. or overnight.
Remove steaks from marinade (discard marinade in bag). Place steaks on grill preheated to high heat. Grill 4 to 5 min., until browned and lightly charred. Flip steaks and continue grilling 3 to 4 min. for medium-rare (145°F/63°C) or to desired doneness. Tent steaks with foil to rest.
Meanwhile, combine mayonnaise, yogourt, orange zest and juice, cilantro, pepper and remaining ½ tsp (2 mL) salt in large bowl. Add slaw and broccoli florets; mix well. Thinly slice steaks and serve with slaw.
Replace Sriracha BBQ Sauce with Sensations by Compliments Spirited Mickie Tequila Lime Habanero BBQ sauce.