One bite and you'll agree this is truly the best shortbread cookie bar recipe, and it's made with only five ingredients! Be sure you are using room temperature butter for best results.
Preheat oven to 325 degrees. Line a 9 x 9 inch baking pan with parchment paper, set aside.
In a mixing bowl, add in the softened butter and use a spoon to stir it until it is smooth in consistency. Stir in the sugar, vanilla, and salt, and mix until combined. Add in the flour and stir until mixture is combined and resembles a coarse crumble.
Press the mixture into the lined baking pan using a spatula or your hands. Bake on center rack in oven for 35 minutes. Remove from oven and immediately sprinkle the top with a tablespoon of sugar (optional). Let cool completely on a wire rack before cutting into squares.
Notes
Use room temperature butter.
If you are using salted butter, just omit the additional salt in the recipe.
The vanilla is not traditionally used in shortbread. Feel free to omit it if you'd like.
Weigh out your flour for the most accurate amounts.
Lining the baking pan with parchment will allow you to lift the bars out of the pan to cut.
Store leftover bars in an airtight container on the counter for 2-3 days. For best results, refrigerate for up to a week.
This shortbread cookie bar recipe is delicious served with a sprinkle of sugar on top. You can also add a chocolate drizzle or frosting with sprinkles.