Beef and Beer Potpie

Name: Beef and Beer Potpie
Ingredients: 2 tablespoons extra-virgin olive oil; 1 pound boneless chuck roast, fat trimmed, cut into ¾-in. pieces; 1 teaspoon kosher salt; 1 teaspoon black pepper; 6 tablespoons all-purpose flour, divided; 1 ½ cups chopped leeks (from 2 medium leeks); 1 cup chopped carrots (from 2 large carrots); 2 tablespoons chopped fresh thyme, divided; ½ cup stout beer (such as Guinness); 2 ½ cups beef stock; 1 cup chopped butternut squash; ½ (17.3-oz.) package of frozen puff pastry sheets, thawed; 1 large egg, lightly beaten; 1 tablespoon water