01 - Preheat oven to 400°F. Line a baking sheet with parchment paper and set aside.
02 - In a large bowl, combine butternut squash, apples, and red onion with olive oil, thyme, salt, and pepper. Toss to coat evenly. Spread mixture on prepared baking sheet and roast for 20-25 minutes until tender and lightly caramelized. Set aside to cool slightly.
03 - While vegetables roast, combine flour and salt in a medium bowl. Using a pastry cutter or your fingers, cut in cold butter until mixture resembles coarse crumbs. Add ice water 1 tablespoon at a time, mixing just until dough comes together. Form into a disc, wrap in plastic wrap, and refrigerate for 20 minutes.
04 - On a lightly floured surface, roll dough into a 12-inch circle. Transfer to parchment-lined baking sheet.
05 - Arrange roasted squash, apples, and onion in center of dough, leaving a 2-inch border. Sprinkle goat cheese over filling and drizzle with honey.
06 - Fold dough edges over filling, pleating as you work around to create rustic border. Brush crust with beaten egg and sprinkle with coarse sugar if desired.
07 - Bake for 25-30 minutes until crust is golden brown and filling is bubbly. Let cool for 10 minutes before slicing and serving.