Begin by peeling, seeding, and cubing your medium butternut squash into 1-inch pieces.

In a large skillet, heat ¼ cup of olive oil over medium heat. Add the chopped onion and sauté until softened and translucent, about 4-5 minutes. Stir in 2 minced garlic cloves and cook for another minute until fragrant.

Add the cubed squash, along with thyme, sage, nutmeg, salt, and pepper. Cook for an additional 5 minutes, stirring occasionally, until the squash begins to soften.

Pour in 1 cup of vegetable or chicken broth, bringing the mixture to a gentle simmer. Cover the skillet and let cook for 10-15 minutes, or until the butternut squash is entirely tender.

Once the squash is soft, remove the skillet from the heat and stir in 1 cup of heavy cream and ½ cup of grated Parmesan cheese. Mix well until the cheese melts into the creamy mixture.

In a separate mixing bowl, combine 1 cup of all-purpose flour, ½ cup of packed light brown sugar, and other crunchy topping ingredients. Cut in cold unsalted butter until the mixture resembles coarse crumbs.

Preheat your oven to 375°F (190°C). Grease a baking dish and transfer the creamy butternut squash mixture into it.

Sprinkle the crumble topping generously over the squash layer. Bake in the preheated oven for 25-30 minutes until golden brown and bubbly.

Once baked, remove the casserole from the oven and allow it to cool for about 10 minutes. Garnish with chopped fresh parsley before serving.