Method:
In a small pan, sauté onion and garlic in oil over medium heat until soft but not browned. Place in a large bowl and add rice, cranberries, sweet potato, apple, walnuts, parsley, and sage. Season with salt and pepper and set aside.
Preheat oven to 375°F. Slice acorn squashes in half, and scrape out seeds and strings. Place face down in large casserole or roasting pan and fill with 1/2 inch of vegetable stock, and bake for 15 to 20 minutes. Remove, reserve any remaining stock, and place face side up in pan. Fill each cavity with about 1/2 to 2/3 cup stuffing. Drizzle with olive oil and any remaining stock, and cover tightly with foil. Bake until squashes are cooked and slightly soft to the touch, about 30 minutes. Remove the foil for the last 5 minutes of baking.