Preheat oven to 350°F and place a cookie sheet inside.
Whisk maple syrup and flour in a large bowl.
Add brown sugar, melted butter, bourbon, vanilla, and salt, mixing well.
Gently stir in eggs, then add half of the pecans.
Pour filling into chilled pie crust, arrange remaining pecans on top, and brush edges with egg wash.
Bake on preheated cookie sheet for 39-43 minutes until set.
Let cool for at least 5 hours.