Preheat the oven to 375°F (190°C).

Cook the jumbo shells according to package instructions until al dente. Drain and set aside.

In a skillet, heat olive oil over medium heat. Add the chopped mushrooms and garlic, and sauté until mushrooms are tender and golden brown.

In a large bowl, mix together the sautéed mushrooms, ricotta cheese, half of the mozzarella cheese, half of the parmesan cheese, salt, and pepper.

Stuff each cooked shell with the mushroom cheese mixture and place them in a greased baking dish.

In a separate bowl, combine the heavy cream with the remaining parmesan cheese. Pour the cream mixture over the stuffed shells.

Sprinkle the remaining mozzarella cheese on top.

Cover with foil and bake for 20 minutes. Remove the foil and bake for an additional 10-15 minutes, until the cheese is bubbly and golden.

Garnish with fresh parsley before serving.