01 -
Preheat oven to 230°C. Line a baking sheet with parchment paper. Arrange mushroom caps gill-side down and roast for 10 minutes. Flip and cook for an additional 5 minutes. For very large caps, extend the first roasting period to 13 minutes. Remove from oven, drain any accumulated liquid, and set aside. Reduce oven temperature to 220°C.
02 -
In a large mixing bowl, combine grated Parmesan, chopped parsley, onion, egg, minced garlic, onion powder, salt, and pepper. Finely chop spinach and incorporate it into the mixture. Add ground chicken and mix until thoroughly combined.
03 -
Season roasted mushroom caps with a pinch of salt and pepper on both sides and arrange top-side down on the baking sheet. Form the chicken mixture into six even portions and place each portion onto a mushroom cap. Gently press to flatten and cover the surface evenly. Lightly spray with cooking spray.
04 -
Bake at 220°C for 15–20 minutes. Remove from oven, top each stuffed mushroom with shredded Italian cheese blend or mozzarella, and return to the oven. Continue baking until the internal temperature of the chicken reaches 74°C and cheese is melted.
05 -
While mushrooms finish baking, gently heat marinara sauce in a saucepan over medium heat until hot but not boiling.
06 -
Remove stuffed mushrooms from the oven. Spoon heated marinara over each mushroom, garnish with additional shredded cheese, Parmesan, and chopped parsley. Serve immediately while hot.