Press one patty into each mushroom cap, going all the way to the edges and up the sides.Spoon 1/4 cup ricotta into each mushroom cap and press to the edges, leaving a dent in the center for the sauce.Spoon 1/4 cup marinara into each mushroom on top of the ricotta layer.Sprinkle 1/4 cup shredded mozzarella cheese on top of each mushroom.Bake in a preheated 375 degree (F) oven for 40 minutes.Garnish with parsley and serve hot.