Preheat your oven to 425°F (220°C). Cut the butternut squash into cubes and spread them on a parchment-lined baking sheet. Drizzle with 2 tablespoons of olive oil, then sprinkle with cinnamon, garlic powder, onion powder, and cayenne. Toss everything together until evenly coated and roast for 15-20 minutes, until the squash is tender and lightly browned.

While the squash is roasting, heat 1 tablespoon of olive oil in a small skillet over medium-high heat. Add the sliced red onion and cook for about 3-5 minutes, stirring occasionally until translucent. Once soft, season with salt and remove from heat, allowing the onion to cool slightly as you prepare the galette.

Once the squash is done roasting, reduce the oven temperature to 350°F (175°C). Prepare a rimmed baking sheet by lining it with parchment paper or a silpat mat. Roll out your pre-made pastry dough into a circle about ¼ inch thick, aiming for a diameter of approximately 12-14 inches, and place it on the prepared baking sheet.

Spread a thin layer of Boursin cheese (or goat cheese) evenly across the center of the dough, leaving roughly a 1-inch border around the edges. Evenly distribute the roasted butternut squash and sautéed red onion on top of the cheese, then arrange the sage leaves over the filling for added flavor.

Gently fold the edges of the galette over the filling, overlapping as needed to secure it. Brush the folded dough with heavy cream for a beautiful glaze, then sprinkle grated parmesan cheese and freshly cracked black pepper on top.

Place the assembled Butternut Squash Galette in the oven and bake for 45-50 minutes, or until the crust turns golden brown and crisp. Once done, remove from the oven and allow it to cool for about 5-10 minutes before slicing. Serve warm, optionally topped with crumbled gorgonzola dolce.