Preheat the oven to 375°F and place parchment paper on 2 large-rimmed baking sheets.
Place the carnival squash halves on the baking tray and season with olive oil, salt, and pepper. Turn over the squash so it is cut side down and bake for 40-45 minutes until cooked through.
Remove from the oven, turn the squash over with tongs and set aside to be filled.
For the Wild Rice
While the squash is roasting, bring the vegetable broth to boil in a small saucepan with high sides. Stir in the rice, cover, and then reduce the heat to low and cook for 45 minutes. Drain the rice and reserve the stock for another use.
For the Filling
While the rice is cooking, add olive oil and vegan butter to a large pan and heat over medium to low-medium heat.
Once the oil is shimmering and the butter has melted, add the leek, celery, and salt; sauté for 3-5 minutes until beginning to brown. Stir in the garlic, chopped mushrooms, and poultry seasoning, and cook for another 5 minutes until the mushrooms begin to brown.
Stir in the chopped apple and cook over low-medium heat for 3-5 minutes until slightly softened.
Remove the saucepan from the heat and stir in the chestnuts, dried cranberries, freshly ground pepper, cooked wild rice, and half of the chopped fresh herbs. Mix, taste, and adjust seasoning as needed.
Fill each roasted carnival squash half with the wild rice mixture. Garnish with the rest of the fresh chopped herbs and serve. Enjoy!
Notes
Some squash skin may be tender enough to eat; others may not. In that case, a knife is handy to pull off the squash flesh.
Store leftovers in an airtight container and refrigerate up to 4 days.
Reheat in a preheated oven at 350°F and bake for 20 minutes, covered with aluminum foil, until warmed through.