Preheat the oven to 350°F.
Lightly season the cut sides of squash with 1 tablespoon olive oil, salt and pepper. Place the halved squash on a baking sheet, flesh side down, and add 1/2 cup water to the pan. Cover the pan tightly with aluminum foil and bake until tender, about 1 hour. Remove from the oven and cool completely.
In a large skillet brown the sausage over medium-high heat, about 6 to 8 minutes. Remove the sausage from the pan and drain on paper towels. Heat the remaining 2 tablespoons olive oil in the pan, and add the onion and bell pepper, sautéing until soft, about 3 minutes. Add the garlic and cook an additional minute. Remove the pan from the heat.
In a large mixing bowl, toss the sausage with the vegetables, bread cubes, chicken stock, half the cheese, parsley and dried sage. Add the egg and stir well to combine. Season to taste with salt and pepper, and mix well.
Divide the stuffing mixture between the baked squash halves, and top with the remaining cheese. Place the filled squash on a baking sheet and place in the preheated oven. Bake until the squash are heated through and the cheese melts, about 25 minutes.
Serve hot as an accompaniment to roast turkey or ham.
Yield: 8 servings