Prep the mushrooms: Heat oven to 400°F (200°C). Gently clean mushrooms with a damp paper towel. Twist out the stems and pat the caps dry. Toss caps with olive oil, a pinch of salt, and pepper.

Pre-bake the caps: Arrange mushrooms, cavity side down, on a parchment-lined sheet. Bake 8–10 minutes to release excess moisture. Drain off any liquid and flip caps cavity side up.

Sauté aromatics: In a skillet over medium heat, melt 2 tablespoons butter. Add garlic and cook 30–60 seconds until fragrant. Don’t brown it.

Make quick Alfredo base: Reduce heat to low. Stir in heavy cream and cream cheese until smooth. Add Parmesan, Italian seasoning, onion powder, red pepper flakes if using, and a pinch of salt and pepper. Simmer 2–3 minutes to thicken slightly.

Add chicken: Stir in chopped chicken and 1 tablespoon butter. Cook 1–2 minutes until heated through and creamy. Taste and adjust seasoning.

Fill the caps: Spoon the chicken Alfredo mixture into each mushroom. Top with mozzarella and a little extra Parmesan.

Bake: Return to the oven for 10–12 minutes, until the cheese is melted and lightly golden.

Broil if needed: For extra color, broil 1–2 minutes. Watch closely.

Finish and serve: Sprinkle with chopped parsley and a crack of black pepper. Let them rest 3–5 minutes to set before serving.