Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper. Cut the acorn squash in half and scoop out the seeds.

Brush the cut sides of the squash with 2 tablespoons of olive oil, then sprinkle with salt and pepper.

Roast the seasoned acorn squash cut-side down for about 30 to 35 minutes until tender.

Heat remaining 1 tablespoon of olive oil in a Dutch oven over medium heat. Sauté the onion, carrot, celery, and garlic for 5 to 7 minutes.

Scoop the roasted squash flesh into the pot. Add vegetable stock, sage, thyme, and rosemary. Simmer for 15 minutes.

Blend the soup until smooth using an immersion blender. Adjust consistency as needed.

Stir in half and half cream to desired creaminess and adjust seasoning with salt and pepper.