Start by seasoning the steak cubes generously with salt and pepper.
In a large skillet, heat the olive oil over medium-high heat. Once hot, add the steak cubes in a single layer. Cook for about 2-3 minutes without stirring to get a nice sear.
Flip the steak cubes and cook for another 2-3 minutes until browned and cooked to your desired doneness (medium-rare is about 130°F). Remove the steak from the skillet and set aside.
In the same skillet, reduce the heat to medium and add the butter. Once melted, add the minced garlic and thyme. Sauté for about 1 minute until fragrant, being careful not to burn the garlic.
Return the steak bites to the skillet and toss them in the garlic butter for about 1 minute to coat.
Remove from heat and garnish with chopped parsley if desired. Serve immediately.