Boil the pasta. Bring about 2 quarts of water to a rolling boil and add 1 tsp of kosher salt. Then add pasta and return to a boil, stirring occasionally for 5 minutes. Reserve 2 cups of the water, then immediately drain. Toss with 1/2 tbsp olive oil. Set aside.
Brown the chicken and sausage. Turn the stove to medium high and add remaining 1/2 tbsp of olive oil to the pot. Once the oil is hot and shimmery, add sausage and ground chicken. Break meat apart with a wooden spoon as it cooks, continuing until the meat is cooked through. Drain the excess fat from the pot, then remove to a paper towel lined bowl. Set aside.
Make the sauce. Add butter to the pot over medium-high heat until melted and bubbling. Add shallots and sauté until softened, about 2-3 minutes. Add sage until fragrant, then add wine to deglaze. Add reserved pasta water, chicken bouillon, seasonings, fresh thyme, and butternut squash. Cover and boil for 8-10 minutes until squash is fork tender.
Pre-heat oven to 400°. Spray and 9x13 inch casserole dish with non-stick cooking spray and set aside.
Remove the thyme sprigs, then using an immersion blender, blend until smooth. Add half and half and blend again until well combined. Add spinach and stir in to coat completely in sauce. Then add meat and pasta and mix until well combined. Add salt to taste and mix again.
Build the casserole. Add the pasta mixture to the prepared casserole dish. Top with shaved cheese.
Bake and serve. Bake at 400° for 25-35 minutes or until cheese is melted and the top begins to turn golden brown. Garnish with fried sage leaves before serving, if desired.