Season the cubed sirloin steak evenly with salt and pepper.
Heat a large skillet over medium high heat until hot.
Add 2 tablespoons of butter to the skillet and let it melt. Once hot, add the steak bites in a single layer, working in batches if needed to avoid overcrowding.
Cook the steak bites for 2 to 3 minutes per side, turning occasionally, until browned and cooked to your desired doneness.
Remove the steak from the skillet and set aside.
Reduce the heat to low and add the remaining 3 tablespoons of butter to the skillet. Once melted, add the minced garlic and cook for about 30 seconds, stirring constantly, just until fragrant.
Remove the skillet from heat, return the steak bites to the pan, and toss to coat evenly in the garlic butter sauce.
Sprinkle with fresh parsley and serve immediately.
Notes
Use a Hot Skillet: Make sure the pan is fully heated before adding the steak so the bites sear quickly and develop a golden crust.
Do Not Overcrowd the Pan: Cook the steak in batches if needed. Overcrowding causes the steak to steam instead of sear.
Remove Steak Before Adding Garlic: Taking the steak out before adding the remaining butter and garlic prevents the garlic from burning and keeps the flavor clean.
Cook to Your Preference: Sirloin cooks quickly, so keep an eye on doneness and remove the steak as soon as it reaches your desired temperature.
Serve Immediately: Steak bites are best enjoyed right away while the butter sauce is warm and the steak is tender.