Step 1: Prepare the Steak. Pat the steak pieces thoroughly dry with paper towels. Season generously with salt and pepper on all sides.
Step 2: Sear the Steak Bites. In a large skillet (cast iron works best), heat the olive oil over medium-high heat until it begins to shimmer. Add the steak bites in a single layer, ensuring not to overcrowd the pan. Sear for 2-3 minutes per side for medium-rare, or until they reach your desired level of doneness. Remove the seared steak bites from the skillet and set them aside on a plate.
Step 3: Make the Garlic Butter. In the same skillet, reduce the heat to medium-low. Add the unsalted butter and let it melt. Add the minced garlic and sauté for about 30 seconds until fragrant, being careful not to burn the garlic.
Step 4: Prepare the Creamy Sauce. Pour in the heavy cream, stirring constantly to combine with the garlic butter. Let the sauce simmer gently for 2-3 minutes, stirring occasionally, until it slightly thickens. Stir in the Dijon mustard and Worcestershire sauce, then season the sauce with additional salt and pepper to taste.
Step 5: Combine Steak with Sauce. Return the seared steak bites to the skillet, tossing them gently in the creamy sauce until they are thoroughly coated and heated through (about 1-2 minutes).
Step 6: Serve. Remove the skillet from heat. Garnish generously with fresh chopped parsley. Serve immediately over your favorite side dishes like mashed potatoes, rice, or pasta.