In a large bowl, whisk together brown sugar, melted butter, egg, and vanilla.

In a medium bowl, whisk together flour and salt. Gradually add flour mixture to butter mixture, stirring until almost combined. Fold in chocolate until combined and no dry streaks remain.

Spray a 9-inch pie plate with baking spray with flour. Press dough into bottom and halfway up sides of prepared plate. Refrigerate until firm, about 30 minutes, or until ready to use.