Start by lining a 9x13-inch metal baking pan with parchment paper. Preheat your oven to 325°F.

In a mixing bowl, cream together 1 cup of softened salted butter, ¾ cup of granulated sugar, 1 tablespoon of vanilla bean paste, and ¼ teaspoon of salt.

In a separate bowl, whisk together 2 cups of all-purpose flour, ¼ cup of powdered sugar, 2 tablespoons of cornstarch, and another ¼ teaspoon of salt.

Take about ⅔ of the shortbread dough and press it evenly into the bottom of the prepared pan.

Mix together ½ cup of dark brown sugar, 2 tablespoons of softened butter, 2 teaspoons of ground cinnamon, 1 tablespoon of cornstarch, 1 teaspoon of vanilla extract, and a pinch of salt until smooth.

Spread the cinnamon filling over the prepared shortbread base, leaving about a ¼-inch border.

Crumble the remaining shortbread dough over the filling, gently pressing it down.

Place the pan in the refrigerator for about 30 minutes to chill the dough.

After chilling, bake for 40-45 minutes until edges are golden brown and the center is set.

Let cool in the pan for about 15-20 minutes, then lift out using the parchment paper to cool completely before cutting.

Whisk together 1 cup of powdered sugar, 1-2 tablespoons of heavy cream, and 1 teaspoon of vanilla until smooth. Drizzle over the cooled bars.