How to Make It
Preheat the oven to 375°. Brush the mushroom caps on both sides with olive oil and season with salt and pepper. Place on a large rimmed baking sheet, gill side down, and bake until tender, about 20 minutes, then turn gill side up.
In a large bowl, combine the cheeses with the lemon zest, basil, three-fourths of the minced garlic and 1 tablespoon of the olive oil. Season the cheese filling with salt and pepper. Mound the stuffing onto the mushroom caps. Bake the stuffed mushrooms until the cheese is melted, about 5 minutes.
Preheat the broiler. Meanwhile, in a small bowl, mix the panko and parsley with the remaining minced garlic and 2 tablespoons of olive oil. Sprinkle the panko mixture over the mushrooms and broil 4 inches from the heat until browned, about 2 minutes. Serve right away.