01 - Preheat the oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, toss butternut squash cubes, 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 squash is tender and lightly caramelized. Let cool slightly.
04 - In a food processor or large bowl, combine flour and salt. Add cold butter and pulse or cut in with a pastry blender until mixture resembles coarse crumbs. Gradually add ice water and mix just until dough forms. Shape into a disk, wrap in plastic, and chill for 20 minutes.
05 - On a lightly floured surface, roll out dough into a 12-inch circle. Transfer to a parchment-lined baking sheet.
06 - Arrange roasted squash, apples, and onions over the center of the dough, leaving a 2-inch border. Drizzle with honey or maple syrup and sprinkle with crumbled cheese if using.
07 - Fold dough edges over the 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 brown and crisp. Cool slightly before slicing and serving.