cut the squash
First, lets cut the butternut squash on cubes. Slice off the stem and bottom of the squash. Slice in half. Using a spoon, remove the seeds. Then, peel the squash with a speed peeler and cut it in small cubes, approx. 1 cm x 1 cm or 1/2 inch x 1/2 inch.
roast butternut squash
Place the butternut squash on a baking sheet lined with parchment paper. Add pancetta (or bacon) cut on small cubes, and the sliced leek. Drizzle with olive oil, season with salt and pepper and toss everything together. Place in the preheated oven. Roast for 30 minutes at 190 °C / 370 °F.
Crumble your cooked chestnuts between your fingers into a large bowl. Add stale bread cut in small cubes, grated parmesan cheese, and diced garlic. Add the herbs, rosemary, thyme, sage, and parsley and season with salt and pepper. Add butter and olive oil. Stir to combine.
Remove the roasted butternut squash with pancetta from the oven. Optionally transfer the roasted butternut squash with pancetta to a smaller oven-safe baking dish (approx. 20cm x 20 cm or 8-inch x 8-inch). Sprinkle the chestnut topping evenly over the butternut squash. Place back in the oven. Roast for 10 - 15 minutes at 200 °C / 390 °F.
Remove the Roasted Butternut Squash with Pancetta and Chestnuts from the oven. Let it sit in the baking dish for about 5 minutes, then serve. Optionally sprinkle with some fresh herbs. Enjoy.