Preheat oven to 350°. Line a 13×9-inch baking pan with parchment paper, letting excess extend over sides of pan. Spray with baking spray with flour.

For crust: In a large bowl, beat butter and granulated sugar with a mixer at medium speed until creamy, 3 to 4 minutes, stopping to scrape sides of bowl. Add egg, beating well. Beat in vanilla.

In a medium bowl, whisk together flour and salt. With mixer on low speed, gradually add flour mixture to butter mixture, beating until combined. Press mixture into bottom of prepared pan. Using a fork, pierce crust several times. Freeze until slightly chilled, about 10 minutes.

Bake until golden brown, 20 minutes. Let cool completely. Reduce oven temperature to 325°.

For filling: In a medium saucepan, cook brown sugar, cane syrup, butter, and granulated sugar over medium heat until sugar is dissolved and mixture boils for 1 minute. Add pecans, cream, vanilla, and salt; boil until mixture thickens slightly, about 3 minutes. Pour hot filling over cooled crust.

Bake until topping darkens slightly and is bubbly, about 20 minutes. Let cool completely in pan.

Using excess parchment as handles, remove from pan, and cut into small diamond-shaped bars.