Salted Caramel Butter Bars

Ingredients

For the Shortbread Crust and Crumb Topping:

2 ½ cups (300g) all-purpose flour

¾ cup (150g) granulated sugar

½ teaspoon salt

1 cup (226g) unsalted butter, very cold and cut into ½-inch cubes

1 teaspoon pure vanilla extract (optional, but highly recommended)