Pat the steak pieces dry with paper towels.
Season the steak with kosher salt and freshly ground black pepper.
Heat a large skillet over medium-high to high heat.
Add 1 tablespoon butter to the hot skillet and let it melt.
Add the steak bites in a single layer.
Sear for 2 to 3 minutes without moving too much, then flip and cook until browned on all sides.
Remove the steak bites from the skillet and set aside.
Add the remaining butter and chopped garlic to the skillet.
Cook for about 30 seconds, stirring often, until fragrant.
Return the steak bites to the pan and toss with the garlic butter.
Sprinkle with chopped parsley.
Serve warm.