Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
Gently clean the mushroom caps with a damp cloth and carefully remove the stems, setting them aside.
Brush the mushroom caps lightly with olive oil and arrange them gill-side up on the prepared baking sheet.
Finely chop the mushroom stems and sauté them in a skillet with a tablespoon of olive oil over medium heat until tender and fragrant, about 5 minutes.
Add the minced garlic to the skillet and cook for another 30 seconds until fragrant, then remove from heat and let cool slightly.
In a mixing bowl, combine the softened cream cheese, cooked mushroom stems, garlic, grated Parmesan, crumbled feta, chopped parsley, salt, and pepper. Mix until smooth and creamy.
Spoon the filling generously into each mushroom cap, pressing slightly to fill evenly, but avoiding overstuffing.
Sprinkle panko breadcrumbs on top of each filled mushroom and drizzle with a little olive oil for extra crispiness.
Bake in the preheated oven for 20-25 minutes, until the tops are golden brown and the filling is bubbly.
Remove from the oven and let rest for 5 minutes to allow the filling to set slightly.
Garnish with additional chopped parsley if desired, then serve warm and enjoy the smoky, cheesy explosion in every bite.
