½ cup fresh mozzarella pearls, drained and patted dry
½ cup thinly sliced fresh basil
2 teaspoons best-quality balsamic vinegar
1 medium clove garlic, minced
Directions
Preheat oven to 400 degrees F.
Combine 2 tablespoons oil, garlic, 1/4 teaspoon salt and 1/4 teaspoon pepper in a small bowl. Using a silicone brush, coat mushrooms all over with the oil mixture. Place on a large rimmed baking sheet and bake until the mushrooms are mostly soft, about 10 minutes.
Meanwhile, stir tomatoes, mozzarella, basil and the remaining 1/4 teaspoon salt, 1/4 teaspoon pepper and 1 tablespoon oil together in a medium bowl. Once the mushrooms have softened, remove from the oven and fill with the tomato mixture. Bake until the cheese is fully melted and the tomatoes have wilted, about 12 to 15 minutes more. Drizzle each mushroom with 1/2 teaspoon vinegar and serve.
Tip: To prepare Portabella mushroom caps, gently twist off the stems of the whole Portabella. Using a spoon, scrape off the brown gills from the underside of the mushroom caps. If you prefer, purchase Portabella mushroom caps, rather than whole mushrooms.