Preheat the oven to 400F (200C). Line a large baking sheet with parchment paper.
Brush the cut sides of the butternut squash halves with 1 tablespoon of olive oil and season lightly with salt and pepper. Place cut-side down on the baking sheet and roast for 40 minutes, or until fork-tender.
While the squash is roasting, heat the remaining 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the ground beef and cook until browned, about 5-7 minutes. Drain any excess fat.
Add the diced onion and minced garlic to the skillet with the beef. Cook for 3-4 minutes until the onions are soft and translucent.
Stir in the ground cinnamon, ground cloves, salt, black pepper, breadcrumbs, and fresh parsley. Mix thoroughly and cook for an additional 2 minutes, then remove from heat.
Remove the tender squash from the oven and carefully flip them over. Divide the beef filling evenly among the four squash halves, packing it gently into the hollowed centers.
Return the stuffed squashes to the oven and bake for another 15 minutes until the topping is hot and slightly crispy. Serve warm.