Heat the grill to high.
Divide the meat into 4 equal portions.
Form each into a 3/4" patty and make a deep depression in the center with your thumb.
Brush the burgers with oil.
Season both sides of each burger with salt and pepper.
Cook the burgers for 5 minutes on each side.
Add crumbled feta cheese and cover with aluminum foil during the last minute of cooking.