Preheat your oven to 375°F and lightly grease a 9x13 inch baking dish with butter or cooking spray. While the oven heats, bring a large pot of salted water to a boil and cook the jumbo pasta shells according to package directions until just al dente—they should still have a slight firmness since they'll continue cooking in the oven. Drain the shells carefully and set them aside on a clean kitchen towel to prevent sticking. I like to lay them flat so they don't seal shut while cooling.

In a large mixing bowl, combine the shredded chicken, cottage cheese, crumbled bacon, ranch dressing mix, egg, ½ cup cheddar cheese, softened cream cheese, and black pepper. Mix everything together thoroughly until well combined and the consistency is uniform. The egg acts as a binder to help hold the filling together, and the cream cheese adds richness to balance the tang of the cottage cheese. I find using a wooden spoon and folding the ingredients together gently prevents overworking the mixture while ensuring even distribution of the ranch seasoning.

Using a small spoon or ice cream scoop, fill each cooked shell with approximately 2-3 tablespoons of the filling mixture from Step 2, packing it gently but not too tightly. Arrange the filled shells seam-side up in the prepared baking dish, fitting them snugly together in rows. This arrangement helps them stay upright during baking and ensures even heat distribution throughout the dish.

Pour the entire 15 oz of alfredo sauce evenly over the filled shells, making sure to coat them generously. Sprinkle the 1.75 cups of freshly shredded cheddar cheese over the top and sides of the shells, distributing it evenly so every shell gets some coverage. Freshly shredded cheese melts much more smoothly than pre-shredded varieties because it doesn't contain anti-caking agents that can make the sauce grainy.

Place the baking dish in the preheated 375°F oven and bake uncovered for 30 to 35 minutes, until the cheese topping is melted and bubbly with light golden brown spots appearing on the edges. The shells are fully cooked, so you're primarily heating the filling through and achieving that beautiful golden crust on top. Let the dish rest for 5 minutes before serving—this allows the sauce to set slightly and makes serving easier without the shells falling apart.