Creating the Apple Butternut Squash Casserole is straightforward if you follow these simple steps:

1. Preheat the Oven: Preheat your oven to 375°F (190°C).
2. Prepare the Vegetables: Peel and dice the butternut squash, then peel, core, and slice the apples. Chop the onion and mince the garlic.
3. Sauté Onions and Garlic: In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the chopped onion and garlic, cooking until softened, about 5 minutes.
4. Combine Ingredients: In a large bowl, combine the diced butternut squash, sliced apples, sautéed onion and garlic, ground cinnamon, nutmeg, salt, and black pepper. Stir well to combine.
5. Add Broth: Pour in the vegetable broth and mix until everything is coated.
6. Transfer to Baking Dish: Pour the mixture into a greased 9×13-inch baking dish, spreading it out evenly.
7. Prepare Topping: In a separate bowl, mix the breadcrumbs and grated Parmesan cheese. Sprinkle this mixture evenly over the casserole.
8. Bake: Place the baking dish in the preheated oven and bake for 30-40 minutes, or until the squash is tender and the topping is golden brown.
9. Cool: Once done, remove from the oven and let it cool for about 10-15 minutes before serving.

These simple steps will guide you in creating this incredible casserole effortlessly.