Steps
Preheat the oven to 375°F (190°C).
Clean the Portobello mushroom cap and remove the stem.
In a skillet, heat olive oil over medium heat. Add minced garlic and sauté for 1 minute until fragrant.
Add chopped spinach to the skillet and cook until wilted, about 2-3 minutes.
Remove from heat and stir in crumbled feta, oregano, salt, and pepper.
Stuff the spinach and feta mixture into the Portobello mushroom cap, pressing down gently.
Sprinkle breadcrumbs on top if using.
Place the stuffed mushroom on a baking sheet and bake for 15 minutes, or until the mushroom is tender and the top is slightly golden.
Garnish with fresh parsley before serving.