I serve this almost every year on Thanksgiving and there are a few reasons you should do the same. First, you can prep the squash a day or two ahead and the rest is minimal and easily thrown together. Second, it cooks up quickly, but also tastes great at room temperature, which means you can squeeze it into your busy cooking schedule then leave it out until you get the big meal on the table.
Preheat oven to 400°F. Line two half sheet pans with parchment paper or silicone mats.
Peel the butternut squash and slice them in half. Scoop out the seeds, and cut into 1-inch cubes. Toss in olive oil and season with a little salt & pepper. Turn out to the prepared sheet pans and roast for 30 to 35 minutes until browned on the outside and soft in the center. Remove from the oven and let cool slightly so they don’t create steam in the bowl and get mushy. When they’re just warm, put them into a bowl and toss with the hazelnut oil, roasted hazelnuts, and rosemary. Savor with delight and gratitude.