Preheat the oven to 375°F (190°C).
Clean the mushrooms with a damp cloth and remove the stems.
Chop the mushroom stems finely and set aside.
In a skillet, heat olive oil over medium heat and sauté the minced garlic until fragrant, about 1 minute.
Add the chopped spinach and mushroom stems to the skillet and cook until the spinach is wilted, about 2-3 minutes.
In a mixing bowl, combine the sautéed mixture, cream cheese, artichokes, mozzarella, Parmesan, salt, and pepper.
Using a spoon, generously fill each mushroom cap with the mixture. Place them on a baking sheet.
Bake the stuffed mushrooms in the preheated oven for 20-25 minutes, until the tops are golden and bubbly.
Remove from the oven and let them cool slightly before serving.