Fire up a charcoal grill for 2 zone grilling.
Tenderize Boneless Ribeye Steak (2), season with Kosher Salt (to taste) and Ground Black Pepper (to taste), drizzle with Balsamic Vinegar (1 tablespoon) and Worcestershire Sauce (1/8 cup).
Place cast iron skillet on hot zone of grill grate. Add Olive Oil (1 tablespoon) and Butter (1 tablespoon).
Add Sweet Onion (1) and Portobello Mushroom (8 ounce) to skillet, season with Kosher Salt (to taste) and Ground Black Pepper (to taste), drizzle with Worcestershire Sauce (1/8 cup). Cook for 10 minutes until brown and tender.
Season each steak with Killer Hogs Steak & Chop Rub (1 tablespoon) and place on the hot zone of the grill.
Cook for 2 minutes each side or until rare - medium rare.
Top each steak with onions and mushrooms; layer on 2 slices of Provolone Cheese (4 slice) on each steak and let it melt on the grill for 30 seconds.
Preheat oven to broil setting. Place Butter (1/4 cup), Dried Parsley (1 teaspoon) and Garlic Powder (1/2 teaspoon) in a small bowl and heat in the microwave for 30 seconds. Stir to combine.
Brush on the top side of each piece of Texas Toast (4 slice), Place the toast in the oven for 1-2 minutes or until brown.
To make the roasted garlic mayo, place the Garlic (1 head) in a small bowl. Mash with a fork until a paste. Add the Mayonnaise (1 cup), Ground Black Pepper (1 teaspoon) and Killer Hogs BBQ Sauce (1 teaspoon) and stir well to combine. Store in the refrigerator until ready to serve.
Slather each piece of Texas Garlic Toast with Roasted Garlic Mayo. Place steak on toast and top with the other slice.