Prepare the Mushrooms:

1. Preheat the Oven: Set your oven to 375°F (190°C) to ensure it’s hot and ready.
2. Clean the Mushrooms: Gently wipe the portobello caps with a damp cloth to remove any dirt. Remove the stems and scoop out the gills with a spoon to create space for the stuffing.
3. Season the Mushrooms: Place the mushroom caps on a baking sheet and drizzle with olive oil. Season with salt and pepper to taste.

Prepare the Caprese Filling:

4. Prepare the Tomatoes and Cheese: In a bowl, combine the halved cherry tomatoes, diced or shredded mozzarella, and chopped basil. Add a pinch of salt and pepper to season.
5. Optional Flavor Boost: If you like, add a clove of minced garlic to the mixture for extra depth of flavor.

Assemble and Bake:

6. Stuff the Mushrooms: Spoon the Caprese mixture into the center of each mushroom cap, pressing gently to pack the ingredients in.
7. Top with Parmesan (Optional): Sprinkle grated Parmesan cheese on top of the stuffed mushrooms for added flavor and a golden, crispy finish.
8. Bake the Mushrooms: Place the stuffed mushrooms in the preheated oven and bake for about 12-15 minutes, or until the mushrooms are tender and the cheese has melted and begun to brown slightly.

Serve:

9. Garnish and Drizzle: Once baked, remove the mushrooms from the oven. For added flavor, drizzle with balsamic vinegar or a balsamic glaze and garnish with extra fresh basil leaves.
10. Enjoy: Serve the stuffed mushrooms warm, as a side dish, appetizer, or light main course.