01 - Preheat oven to 375°F. Line a baking sheet with parchment paper.
02 - Remove stems from mushroom caps and gently scoop out some of the inside flesh to create room for filling. Wipe caps clean and set aside.
03 - Heat olive oil in a skillet over medium heat. Add minced garlic and cook until fragrant, about 30 seconds. Add chopped spinach and sauté until wilted, 2–3 minutes.
04 - Stir in chopped artichoke hearts and cook for 1–2 minutes until warmed through. Remove from heat and let cool slightly.
05 - In a mixing bowl, combine cream cheese, sour cream, Parmesan, mozzarella, salt, pepper, and red pepper flakes. Mix until smooth and well blended.
06 - Fold the cooked spinach and artichoke mixture into the cheese mixture until evenly distributed.
07 - Spoon the filling generously into each mushroom cap, mounding slightly. Arrange stuffed mushrooms on the prepared baking sheet.
08 - In a small bowl, mix breadcrumbs with melted butter. Sprinkle evenly over the stuffed mushrooms.
09 - Bake for 20–25 minutes until mushrooms are tender and topping is golden brown.
10 - Let cool for 5 minutes before serving warm.