Adjust oven rack to lowest position and heat oven to 400 degrees.
Mix cream cheese, confectioner’ sugar, 2 tablespoons of the cornstarch, and 1 of the egg yolks in medium bowl; set aside.
Meanwhile heat remaining tablespoon of cornstarch and ⅓ cup of water in a medium saucepan over low heat, whisking frequently, until pasty thick.
While cornstarch heats, warm brown sugar and corn syrup in a small saucepan over medium heat until sugar has almost dissolved. Whisk remaining 2 yolks, vanilla, and salt in a medium bowl. Slowly whisk warm sugar mixture into yolks and then egg-sugar mixture into cornstarch mixture. Whisk in chocolate, and then pecans. Cool slightly to thicken
Meanwhile, unfurl pie dough on a lightly floured surface and roll to about 13-inches in diameter. Slide onto a cookie sheet or pizza pan and spread evenly with cream cheese mixture, leaving a 2-inch border. Pour tepid chocolate mixture over cream cheese mixture. Fold pastry border over the chocolate. Brush dough perimeter with egg white and sprinkle with a little sugar.
Bake galette until golden brown and bubbly, 25 to 30 minutes. Loosen with a metal spatula and slide onto a wire rack to cool slightly. Serve warm.
Recipe by Three Many Cooks at https://threemanycooks.com/recipes/sweet-treats/chocolate-pecan-cheesecake-galette/