Get the steak to room temperature. Season all sides with Dad's All Purpose rub. Set aside.
To make the cowboy butter sauce, in a skillet, add a stick of unsalted butter, minced garlic, diced shallot, fresh parsley and chives, dry thyme, a dash of cayenne pepper, crushed red pepper flakes, dijon mustard, Worcestershire sauce and Dad's steak seasoning. Melt the ingredients over low heat until everything is nicely mixed together.
Preheat the grill to 500 degrees and set it for direct heat.
Sear the steak flipping it every 30-40 seconds to get an even sear and cook throughout. To achieve the perfect medium rare, the final internal temperature on the steak should be 120 degrees when removing off the grill.
Remove the steak off the grill and let it rest for 10 minutes.