In a bowl, combine the butter, garlic, parsley, Worcestershire, and lemon juice. Place on some plastic wrap and roll into a log. Refrigerate until firm.
Combine the mustard and honey in a small bowl. Spread all over the steak. Lay bacon strips against the grain. Sprinkle the cheddar cheese, then add the onions and bell peppers into an even layer. Roll into a log.
Secure with butcher's twine every 1.5 inches. Slice between the twine to make pinwheels.
Heat your grill or cast iron pan over medium high heat with some oil. Cook the pinwheels about 3-5 minutes per side, or until they reach desired doneness.
Top with a slice of cowboy butter while still hot.