01 -
Turn your oven on to 375°F (190°C). Cover your baking tray with a sheet of parchment paper. Coat both sides of the mushroom caps with olive oil and lay them out gill-side up on the baking tray.
02 -
Let the mushroom caps bake for around 10 minutes until they start giving off their liquid. This will stop the finished dish from being overly watery.
03 -
While the mushrooms are in the oven, warm the leftover olive oil in a big pan on medium heat. Toss in the garlic and onions, cooking until soft—this takes about 3-4 minutes. Then, stir in the spinach and cook for another 2-3 minutes until it’s wilted. Take the pan off the heat and let the mix cool for a few minutes.
04 -
Mix the cooked spinach, garlic, and onion mixture with ricotta, Parmesan, salt, pepper, and nutmeg (if you’re using it) in a bowl. Stir everything together so it’s combined evenly.
05 -
Scoop the cheese-spinach mix into the mushroom caps, dividing the filling evenly. Sprinkle shredded mozzarella cheese over the top of each filled mushroom.
06 -
Put the stuffed mushrooms back in the oven for 15-20 minutes. You’ll know they’re done when the cheese gets all bubbly and starts browning.
07 -
Sprinkle more Parmesan cheese if you want, and serve the mushrooms while they’re nice and warm!