Preheat your oven to 400°F (200°C). Slice the acorn squash in half and scoop out the seeds. Coat the cut sides with olive oil, sprinkle with salt and pepper, and place cut-side down on a parchment-lined baking sheet. Roast for 25–30 minutes until tender.

In a large skillet over medium heat, cook the Italian sausage, breaking it apart, for about 5–7 minutes until browned and cooked through. Drain excess fat if necessary.

Add the diced onion and celery to the skillet with the sausage and cook for an additional 3–4 minutes until softened.

Stir in the diced apple and thyme, cooking for 2–3 minutes until the apples are just tender. Season the filling with salt and pepper to taste.

Flip the roasted squash cut-side up and spoon the sausage-apple mixture generously into each half.

Return the stuffed squash to the oven and bake for an additional 5–7 minutes.

Remove from the oven and let cool slightly before serving. Drizzle with maple syrup or balsamic glaze if desired.