Soak wooden skewers in water for at least 30 minutes if using wooden skewers.
Prepare the marinade by combining olive oil, garlic powder, rosemary, salt, and pepper in a bowl.
Toss the filet mignon cubes in the marinade, ensuring each piece is well-coated. Let it marinate for at least 15 minutes at room temperature.
Preheat the grill to medium-high heat, ensuring it's ready for cooking.
Thread the marinated filet mignon cubes onto skewers, leaving a little space between each piece for even cooking.
Place the skewers on the preheated grill and cook for 3-4 minutes per side for medium-rare, adjusting time for desired doneness.
Remove the skewers from the grill and let them rest for a few minutes before serving.