1 medium-sized acorn squash, unpeeled
2-3 tablespoons softened unsalted butter, or as needed
Kosher salt and freshly-ground black pepper, to taste
1/2 yellow or white onion, finely chopped
2-3 cloves fresh garlic, finely minced
5-6 fresh white or Crimini mushrooms (cleaned, trimmed and finely chopped)
1/2 teaspoon fresh (or dried) tarragon leaves, or to taste
1/2 teaspoon fresh (or dried) thyme leaves, or to taste
1/2 teaspoon fresh (or dried) oregano leaves, or to taste
1 can Campbell’s Cream of Mushroom soup (undiluted)
8-10 slices sharp cheddar cheese (thinly sliced), or to taste
1/2 cup freshly-grated Parmigiano-Reggiano cheese, or as needed
Preheat oven to 350°. With a sharp knife carefully pierce squash in 3-4 places (it will later be cut into individual slices). Briefly cook squash in a microwave oven on high power, only until it softens enough to slice. Remove squash from the microwave and carefully cut it in half horizontally. Remove and discard the seeds, then cut each half into individual slices about 1-inch thick. Place the slices on a cookie sheet and very lightly coat the top of each slice with softened butter. In a small bowl mix together all the remaining ingredients, except for the cheeses. After the mixture is well blended, place a scant 1/4 teaspoon of butter in the center of each slice, then generously fill the center of each slice with the mushroom mixture. Place cheddar cheese over the top of each slice and generously sprinkle grated Parmigiano-Reggiano cheese over the top. Bake until the squash is tender and the cheese has melted and starts to brown. NOTE: The skin of this squash is both edible and very delicious — there is no need to peel! — Makes 6-8 slices.