01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - Toss butternut squash, apple slices, and red onion with olive oil, thyme, salt, and pepper. Spread evenly on the prepared baking sheet.
03 - Roast for 20 to 25 minutes, stirring once, until the squash is tender and lightly caramelized. Let cool slightly.
04 - Combine flour and salt in a food processor or bowl. Add cold butter and pulse or cut in until mixture resembles coarse crumbs. Add ice water gradually, mixing just until dough forms. Shape into a disk, wrap, and chill for 20 minutes.
05 - On a lightly floured surface, roll dough into a 12-inch circle. Transfer to a parchment-lined baking sheet.
06 - Arrange roasted squash, apples, and onions over dough center, leaving a 2-inch border. Drizzle with honey or maple syrup and sprinkle with cheese if using.
07 - Fold dough edges over filling, pleating as needed. Brush crust with beaten egg and sprinkle with coarse sugar if desired.
08 - Bake for 25 to 30 minutes until crust is golden and crisp. Cool slightly before slicing and serving.