Cube top sirloin steak into about 1" pieces.
Put steak into a bowl and add minced garlic, salt, and pepper. Stir so seasonings are evenly spread on each piece. Cover and let sit overnight or 8 hours in refrigerator.
Melt 1/2 cup butter.
Heat up grill to 375°F.
Place cubed steak onto skewers. Spread melted butter onto each piece with a brush.
Rotate every 2 minutes and continue to add melted butter until pieces are cooked through on grill. Meat should be 150° for medium/well-done steak.
Let meat rest for about 5 minutes. Serve & enjoy!