01 - In a large bowl, combine flour and salt. Add cold butter and rub into flour with fingertips until mixture resembles coarse crumbs. Gradually add ice water, mixing until dough just forms. Shape into disk, wrap in plastic, and refrigerate at least 30 minutes.
02 - Set oven to 400°F. Line a baking sheet with parchment paper.
03 - Toss zucchini, bell pepper, onion, and cherry tomatoes with olive oil, salt, and pepper. Spread on prepared sheet and roast 15 to 20 minutes until slightly tender; cool before assembling.
04 - On a lightly floured surface, roll dough into a 12-inch circle and transfer to parchment-lined baking sheet.
05 - Arrange roasted vegetables in center, leaving a 2-inch border. Sprinkle with goat cheese and thyme. Fold edges over filling, pleating as needed.
06 - Brush crust with beaten egg mixed with milk.
07 - Bake for 25 to 30 minutes until crust is golden and crisp. Cool for 10 minutes before slicing.