Peel the squash with a sturdy vegetable peeler. Slice off the top and bottom, stand it upright, and cut in half lengthwise. Scoop out the seeds with a large spoon. Cut each half into slices, then crosscut into 1-inch cubes — keep pieces consistent so they cook evenly. Pat dry if wet, then toss in a bowl with olive oil, salt, and pepper until evenly coated. Season generously. Line your sheet pan(s) with parchment or foil before you start.

Preheat oven to 400–425°F (let it fully preheat before adding squash). Spread cubes in a single layer on a sheet pan — no crowding or overlapping, or they'll steam instead of roast. Use two pans if needed. Roast in the center of the oven for 30–50 minutes: 1-inch cubes at 400°F take 30–35 minutes; larger pieces or 425°F take 40–50 minutes. At the 15–20 minute mark, shake or flip the squash for even browning. Continue roasting until edges are golden and caramelized.

Done when edges are browned and caramelized and a fork slides through the thickest piece with no resistance — tender all the way through, not mushy. If browning outside but still firm inside, lower heat and roast another 5–10 minutes. Rest on the pan a couple of minutes before serving. Finish with salt and pepper, or add feta, balsamic glaze, fresh sage, or toasted walnuts. Leftovers keep 3–4 days refrigerated. Reheat at 350°F or microwave. Don't crowd the pan — use extra pans if needed.