In a medium bowl, whisk together the marinade: 3 tablespoons of olive oil, balsamic vinegar, garlic powder, salt, and pepper.

Pat the steak pieces dry with paper towels. Add them to the bowl with the marinade and coat well. Cover and marinate for at least 30 minutes. (If not making the steak tips right away, you can refrigerate in the marinade for up to 24 hours.)

When you are ready to cook, turn on the stovetop fan. Heat a large cast iron skillet over medium-high to high heat. It's ready when a drop of water on it sizzles.

Once the pan is hot, add the remaining tablespoon of olive oil. Add the steak tips in a single layer. (Do not crowd the pan - cook in batches if they don’t fit.) Cook for 30 to 60 seconds per sides (all sides, not just 2 sides), until browned on all sides. If you want a certain level of doneness, check with a meat thermometer – 120 degrees F (49 degrees C) for rare, 130 degrees F (54 degrees C) for medium rare, 140 degrees F (60 degrees C) for medium, 150 degrees F (66 degrees C) for medium well, or 160 degrees F (71 degrees C) for well done.

Remove the sirloin tips from the pan immediately to prevent overcooking. Rest for 5 minutes before serving.

Serve with chimichurri sauce, if desired.