Remove the steak from the refrigerator about 15-20 minutes before cooking. Pat the steak pieces thoroughly dry with paper towels and season generously with salt and black pepper on all sides.

Place a large, heavy-bottomed skillet over medium-high heat. Add the olive oil and let it get shimmering hot.

Add half of the steak pieces to the hot skillet in a single layer. Sear for 1.5-2 minutes per side until a nice, browned crust forms. Remove the first batch of seared steak to a plate.

Add the remaining steak pieces to the skillet and repeat the searing process. Once seared, remove them to the same plate.

Reduce the heat to medium-low. Add the unsalted butter to the same skillet. Once melted, add the minced garlic and red pepper flakes (if using). Sauté for about 30-60 seconds, until fragrant.

Return all the seared steak bites to the skillet. Toss them gently in the fragrant garlic butter, ensuring each piece is coated. Sprinkle with fresh chopped parsley. Cook for another 30 seconds to allow the flavors to meld. Serve immediately.