Preheat the oven to 375°F (190°C) and lightly grease a baking sheet.

Brush both sides of the portobello mushrooms with olive oil, then place them gill-side up.

Season the mushrooms with salt and pepper.

Sauté minced garlic in olive oil over medium heat for about 1 minute.

Add the chopped spinach, cooking until it wilts, then remove from heat.

Stir in halved cherry tomatoes, breadcrumbs, Parmesan cheese, Italian seasoning, and a pinch of salt and pepper into the spinach mixture.

Spoon the filling evenly into each mushroom cap, then top generously with shredded mozzarella cheese.

Bake for 15–18 minutes or until mushrooms are tender and cheese is melted and bubbly.

Garnish with fresh basil or parsley and serve warm.