Pour whiskey, mustard, soy sauce, sweet red chili sauce and brown sugar into ziplock bag. Squishy to combine.

Add steak, shake and swoosh it around so steak gets covered in marinade. Close bag.

Place in refrigerator and let marinate for about 2 hours.

Over medium high heat grill steak for approximately 5 minutes per side. 10-12 minutes will get you a rare steak. Remove and let rest for 5 minutes before carving.