Step 1: Pat the steak pieces thoroughly dry with paper towels. Season generously with salt and black pepper on all sides.
Step 2: Heat 1 tablespoon of olive oil and 1 tablespoon of unsalted butter in a large heavy-bottomed skillet (cast iron works best) over medium-high heat until the butter is melted and shimmering.
Step 3: Add half of the steak bites to the hot skillet in a single layer, ensuring they are not overcrowded. Sear for 2-3 minutes per side until beautifully browned and a crust has formed. Cook to your desired doneness (medium-rare for 2 minutes per side, medium for 3 minutes per side). Remove the seared steak from the skillet and set aside on a plate. Repeat with the remaining steak bites, adding another tablespoon of butter if needed.
Step 4: Once all steak is seared and removed, reduce the heat to medium-low. Add the remaining 2 tablespoons of butter to the skillet. Once melted, add the minced garlic and Italian seasoning (if using). Sauté for about 30 seconds to 1 minute, or until fragrant. Be careful not to burn the garlic.
Step 5: Return all the cooked steak bites to the skillet. Toss them gently in the garlic butter sauce to coat evenly. Cook for another 1 minute, stirring occasionally, just to heat through and ensure every piece is coated.
Step 6: Remove from heat, garnish with fresh chopped parsley, and serve immediately. Leftovers can be stored in an airtight container, such as Basics Glass Food Storage, in the refrigerator for up to 3 days.