Several hours before cooking, place portobello mushrooms in a large sealable plastic bag. Pour in some olive oil, enough to coat all mushrooms, plus some excess. Sprinkle a little salt and some cracked pepper into the bag. Add about a tablespoon of minced garlic. Seal bag and shake. Refrigerate for a few hours.
Preheat grill to high, remove the mushrooms from the bags and place on grill for 5 to 7 minutes per side or longer; you really can't overcook them. Flip them every few minutes or so.
A viewer, who may not be a professional cook, provided this recipe. The FN chefs have not tested this recipe and therefore, we cannot make representation as to the results.