Cut the sirloin steak into bite-sized pieces and pat dry.
Season the steak pieces with salt and pepper.
Heat olive oil in a large skillet over medium-high heat.
Add the steak bites in a single layer; avoid overcrowding.
Sear for 2-3 minutes on each side until browned.
Remove steak bites and let them rest on a plate.
In the same skillet, reduce heat to medium and add the butter.
Once melted, add minced garlic and sauté for about 1 minute.
Return steak bites to the skillet and toss in garlic butter.
Garnish with fresh parsley before serving.