Prepare the Steak: Slice the steak into roughly 2-inch pieces and place them in a mixing bowl.
Season the Steak: In a small bowl, combine all the Cajun seasoning blend ingredients. Add the seasoning mix to the steak bites in the mixing bowl and toss to ensure the steak is evenly coated.
Preheat the Skillet: Heat a large, heavy-bottomed skillet over medium-high heat. Allow the skillet to heat for several minutes until you see wisps of smoke.
Sear the Steak (in batches): Add 1 tablespoon of vegetable oil to the hot skillet and swirl to coat the pan. Add about half of the steak bites to the skillet, being careful not to overcrowd the pan. Sear the steak bites for 2 minutes without flipping, then flip and sear the other side for another 2 minutes until well browned. Remove the steak bites from the skillet and set them aside on a plate. Repeat the process with the remaining vegetable oil and steak bites.
Make the Garlic Butter: Reduce the heat to medium-low and, using the same skillet (do not wash it), add the butter. Once the butter has melted, add the minced garlic and cook for about 30 seconds, stirring frequently. Use a wooden spoon to scrape up any browned bits from the bottom of the pan for added flavor.
Combine and Serve: Turn off the heat and return the seared steak bites to the skillet. Stir well to coat the steak in the garlic butter. Serve the steak bites hot, garnished with minced fresh parsley.