Preheat the Oven : Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper or lightly grease it with olive oil.
Prepare the Mushrooms : Gently clean each mushroom with a damp paper towel (avoid soaking them in water). Remove the stems and finely chop them — you’ll use them in the filling. Lightly brush the mushroom caps with olive oil and place them cap-side down on the baking sheet.
Cook the Filling Base : In a skillet, melt butter over medium heat. Add the chopped mushroom stems, garlic, and green onions. Sauté for about 3–4 minutes, until tender and fragrant. Remove from heat and let it cool slightly.
Prepare the Filling : In a mixing bowl, combine cream cheese, Parmesan, breadcrumbs, parsley, lemon juice, salt, pepper, and paprika. Add the cooked mushroom stem mixture and stir until everything is well blended and creamy.
Stuff the Mushrooms : Using a small spoon, fill each mushroom cap with the cream cheese mixture. Mound it slightly for a full, rounded top.
Bake the Mushrooms : Place the baking sheet in the oven and bake for 18–20 minutes, until the tops are golden and slightly crispy.
Garnish and Serve : Remove from the oven and let them cool for a couple of minutes. Garnish with fresh parsley or a light sprinkle of Parmesan before serving warm.