Prep Time: 10 minutes
Cook Time: 10 minutes
Total Time: 20 minutes
Servings: 4
Preheat grill or broiler pan.
Clean mushrooms and remove stems and gills.
Brush olive oil lightly over both sides of each mushroom cap.
Place mushrooms on grill or broiler pan, stem side down, and cook 5 minutes.
Remove from heat and invert.
Meanwhile, combine mozzarella and tomatoes in a small bowl.
Combine oregano, garlic powder, salt and pepper, sprinkle over cheese and tomatoes, toss to coat.
Spoon 1/3 cup cheese and tomato mixture into each mushroom cap.
Return pan to heat; continue cooking until filling is hot, about 5 minutes.
Drizzle 1 teaspoon balsamic dressing over filling in each mushroom.