My gf makes this dish with butternut squash, and it is REALLY good!! Here is her recipe as adapted from a Cooks.com recipe for Stuffed Autumn Acorn Squash. We made it with acorn squash a few times so if that's what you have you can use it just look up the cooks dot com recipe and go from there.
Cary's Squash Casserole
2 to 3 Cups cooked butternut squash
4 tbsp. unsalted butter, melted (1/2 stick)
1 lb. hot Italian sausage
1 box cornbread stuffing mix
1 1/2 c. chicken broth
8 oz. mushrooms
1/2 c. yellow onion
1/2 c. corn
1/4 c. red bell pepper
1/4 c. toasted pine nuts
3 ea. cloves garlic, minced
2 tbsp. fresh parsley, chopped
Sauté onions, corn and bell pepper until softened, add mushrooms and garlic half-way through.
In a bowl, mix together raw sausage, cooked squash, uncooked stuffing mix, broth, 1/2 stick of melted butter, sautéed vegetables, pine nuts and parsley.
Spoon mixture into a number 10 cast iron skillet.
Cover and bake at 350F for 1 hour or until temp in center measures 165F
Remove cover and continue to bake uncovered until top crisps, about 15 minutes.