Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish.
In a large mixing bowl, combine the chopped artichoke hearts, spinach, morels, chanterelles. Mix well.
Add olive oil to a large saucepan over medium-high heat. Add onions and peppers and heat until softened, stirring occasionally. Add garlic and stir another minute or so.
Add white wine and stir until wine has mostly evaporated.
Add artichoke and spinach mixture, turn down heat to medium, and stir until spinach is wilted and mixture is hot. Turn offf heat and turn out mixture to large, heat-proof mixing bowl. Let cool.
Add ricotta, parmesan, chicken, onion powder, garlic powder and balsamic vinegar to onion mixture and mix thoroughly. Add salt and pepper to taste. Cover bowl and set aside.
Cook the jumbo pasta shells according to the package instructions to ensure they are al dente. Once cooked, drain the shells and set them aside on a parchment lined cooking sheet to cool slightly.
Take each cooled shell and generously and gently fill each with the artichoke-spinach-chicken mixture with a spoon. Arrange the stuffed shells (stuffed side up) in a baking dish. 16 filled shells should fit 4-across, 4-long.
Pour the marinara sauce evenly over the stuffed shells, making sure each shell is well-coated. Cover the dish and bake for 30 minutes.
Remove dish from oven, remove cover. Sprinkle shredded mozzarella and parmesan evenly over shells. Then pour heavy cream very sparingly over and in between shells so all cream is used, but evenly.
Place back into oven, uncovered, for another 15 minutes until brown and bubbly. Remove from oven and let sit for 15 minutes. Serve!
Notes
You might want to cook extra shells, in case any break during cooking or filling process. If using dried mushrooms, reconstitute per package instructions.