Preheat your air fryer to 375°F (190°C).
Heat 1 tablespoon extra virgin olive oil in a skillet over medium heat. Sauté the chopped 6 cups fresh spinach and 1 teaspoon minced garlic until the spinach is wilted.
In a mixing bowl, combine the sautéed spinach, chopped 1 tablespoon fresh basil, 1 tablespoon fresh parsley, grated 1 cup Fontina cheese, 1 ½ cups Japanese-style breadcrumbs, ½ cup unsalted butter, 1 teaspoon salt, 1 teaspoon ground black pepper, 1 teaspoon dried oregano and 1 teaspoon Paprika. Stir until well combined.
Spoon the spinach mixture into each 12 large mushrooms cap, pressing gently to pack the stuffing in.
Lightly coat the air fryer basket with cooking spray and arrange the stuffed mushrooms in a single layer.
Air fry for 8-10 minutes or until the mushrooms are tender and the stuffing is golden brown.
Remove from the air fryer, optionally sprinkle with extra fresh herbs or cheese, and serve warm.