Wash the mushrooms and drain them on paper towels upside down then pat dry. Turn them upright.

Spray the mushrooms with nonstick cooking spray.

Sprinkle 1/2 teaspoon salt and garlic powder over the mushroom caps.

Add a few cracks of pepper then place the seasoned side onto a medium high grill or grill pan.

Follow the same procedure for the bottoms of the mushrooms and allow to cook for 2-3 minutes on one side before flipping over.

Top each mushroom cap with one slice of tomato and cheese.

Close the grill for 1 minute to let cheese melt slightly.

Place caps onto a serving plate.

Add one large basil leaf to each cap.

Drizzle extra virgin olive oil over the tops, season to taste with more salt and pepper if desired and serve warm or room temperature.