Preheat the broiler.Grease a sheet pan (preferably with sides) with olive oil.Mix together well the Parmesan, butter, greek yogurt, lemon zest and juice, basil, ¼ tsp black pepper, onion powder, and celery salt. Set aside.Rinse and pat tilapia filets dry. Lay filets on greased pan. Season both sides with a bit of salt and pepper.Broil a few inches away from the heat for 2 minutes on one side.Flip and broil for 2 minutes on the other side.Remove from oven and generously spread the Parm topping on top.Broil for 2 more minutes or until golden on top. Fish is done when easily flakes. Do not overcook.