Preheat oven to 190 degrees celsius.
Peel the mushrooms and remove the stalk.
Finely dice the mushroom stalk and place it into a large mixing bowl.
To the mixing bowl add the ricotta, parmesan cheese, chopped baby spinach, parsley, garlic and salt. Mix until well combined.
Spoon the ricotta mixture into the mushroom cups and place stuffed mushrooms into a baking dish.
Add the vegetable stock (or water) to the base of the dish (this will help to steam and cook the mushrooms).
Loosely cover the mushrooms with aluminium foil and put into the oven.
Bake for approximately 30 minutes. Remove aluminium foil and bake for a further 10 minutes.
Remove from oven and serve.
