Preheat your oven to 350°F (175°C). Prepare an 8x8 inch baking pan by greasing it and lining it with parchment paper.

In a mixing bowl, add 1 cup softened butter and ¾ cup superfine white sugar, cream together until light and fluffy. Add 1 tablespoon pure vanilla extract and mix until fully incorporated.

In a separate bowl, whisk together 2 ½ cups all-purpose flour and ¼ teaspoon salt.

Gradually add the dry ingredients to the butter mixture, mixing until just combined to avoid overworking the dough.

Press half of the dough into the prepared pan, reserving the remaining half of dough for the top layer. Cover the remaining dough and chill the fridge along with the dough in the pan for 15 minutes.

Transfer the pan to the preheated oven in the center of the middle rack and bake for 10 minutes. The shortbread will still look somewhat underbaked, but that’s ok, we will bake it again once we add the filling. Remove from the oven and allow to cool while you work on the cinnamon filling.

In a small bowl, add ¼ cup melted butter, ½ cup brown sugar, 1 teaspoon cinnamon, and 1 teaspoon vanilla extract and mix until combined.

Drop the prepared cinnamon filling by the spoonful onto the partially baked shortbread crust and spread gently into an even layer.

Roll out the remaining shortbread dough or use your hands to create flat discs about ¼ inch thick. Place flat clusters of dough on top of the filling to loosely form a lid.

Place the assembled bars back in the oven and bake at 350°F for 30 minutes, until the edges are beginning to brown. The center may look slightly underdone, but this will make for a more tender shortbread. As oven temperatures can vary, be sure to check the bars at the 25 minute mark to avoid overbaking. Once fully baked remove from the oven and allow the bars to completely cool to room temperature.

In a small bowl, add 1 cup powdered sugar, 1 ½ teaspoons pure vanilla extract, ½ teaspoon cinnamon and 3 ½ teaspoon water. Mix together with a fork until fully combined and smooth.

Pour the icing on the cooled shortbread and spread into an even layer. Allow the icing to stand on top of the bars for about 15-20 minutes to set. (optional) Cut into slices and enjoy!!