Preheat your oven to 190°C (375°F). Line a baking sheet with parchment paper for easy cleanup.

Prepare the portobello mushrooms: Gently wipe the mushroom caps clean with a damp cloth. Carefully remove the stems by wiggling them gently or using a small knife. If desired, scrape out the dark gills from the underside of the mushroom caps using a spoon; this is optional but can create more space for the filling and a cleaner look.

In a medium bowl, combine the halved cherry tomatoes, diced fresh mozzarella, chopped fresh basil, minced garlic, 15ml (1 tbsp) of olive oil, salt, and pepper. Gently toss to combine all the ingredients evenly.

Brush the outside and inside of the portobello mushroom caps with the remaining 15ml (1 tbsp) of olive oil. Place the prepared mushroom caps, hollow side up, on the prepared baking sheet.

Generously stuff each portobello mushroom cap with the Caprese mixture. Ensure the filling is mounded slightly.

Bake in the preheated oven for 15-20 minutes, or until the mushrooms are tender and the mozzarella is melted and slightly golden.

Once baked, carefully remove the stuffed mushrooms from the oven. Drizzle each mushroom generously with balsamic glaze. Garnish with a few extra fresh basil leaves, if desired.

Serve immediately and enjoy these delicious Caprese Stuffed Portobello Mushrooms as an appetizer or a light main course.