My mother Susan was known far and wide for her out of this world squash casserole. Below is her recipe. I have always had great suspicion that she left SOMETHING out of the recipe she shared with folks, or maybe it was just her years of practice. After attempting this for years on my own now I think I've finally mimicked the flavors.

Ingredients

1 bag of stuffing (Mom used Pepperidge Farm cubed)
2 cans of squash (Mom used Margaret Holmes; fresh is good, but canned gives that signature flavor)
1 can cream of chicken or mushroom soup
1 cup sour cream
1 cup shredded cheddar cheese
1/2 stick of butter
1 onion, chopped
1–2 tbsp of oil (your choice, for sautéing)

Directions

Sauté the Onion

In a nonstick pan, heat your choice of oil over medium heat. Add the chopped onion and sauté until softened and translucent. Transfer the onion to a large mixing bowl.

Prepare the Filling

In the same mixing bowl, add the squash (drained if using canned), cream of chicken or mushroom soup, sour cream, and shredded cheddar cheese. Mix thoroughly until everything is well combined.

Toast the Stuffing

In the same pan, melt the butter over medium heat. Add the stuffing mix and stir constantly until lightly toasted and fragrant. Remove from heat.

Assemble the Casserole

Grease a baking dish. Spread half of the toasted stuffing mix evenly across the bottom. Pour the squash mixture on top and smooth it out with a spatula. Cover the squash layer with the remaining stuffing mix.

Bake

Preheat your oven to 350°F. Bake the casserole for 30–45 minutes, or until golden brown and bubbling.

Notes:

If you're using fresh squash, slice it thin and sauté with the onions until tender before mixing into the filling.
Homemade cream of mushroom soup can add a delicious twist, but the canned version works just as well.