1. 1. Cook the pasta shells: Bring a large pot of salted water to a boil. Add the jumbo pasta shells and cook according to package directions until al dente. You want them firm enough to handle without tearing. Drain the shells and toss them with a tablespoon of olive oil to prevent sticking. Set aside to cool slightly.

2. 2. Prepare the buffalo chicken filling: In a large bowl, combine the shredded cooked chicken, softened cream cheese, 1/2 cup buffalo wing sauce, and 1/2 cup ranch dressing. Mix well until all ingredients are thoroughly combined and the mixture is creamy.

3. 3. Add the cheeses to the filling: Stir in 1/2 cup shredded mozzarella cheese and the crumbled blue cheese (if using) into the buffalo chicken mixture. Ensure the cheese is evenly distributed throughout the filling.

4. 4. Preheat oven and prepare baking dish: Preheat your oven to 375 F (190 C). Lightly grease a 9×13 inch baking dish with cooking spray or a little olive oil.

5. 5. Stuff the pasta shells: Carefully pick up each cooked jumbo shell and spoon a generous amount of the buffalo chicken filling into it. Arrange the stuffed shells in a single layer in the prepared baking dish.

6. 6. Bake the stuffed shells: Once all shells are stuffed and arranged, sprinkle the remaining mozzarella cheese over the top. Bake for 25-30 minutes, or until the cheese is melted and bubbly and the shells are heated through.

7. 7. Garnish and serve: Remove the baking dish from the oven. Drizzle with a little extra buffalo sauce and sprinkle with chopped green onions for a fresh finish. Serve hot with additional ranch dressing on the side.