Line an 8x8 pan with parchment, set aside. Parchment will help you remove the cookies from the pan when they are hot, don't skip using!
In the bowl of your stand mixer or a medium bowl with hand mixer, cream together powdered sugar and butter until smooth and creamy.
Add vanilla and salt and combine.
Add flour and mix on low until crumbly.
Using your hands, bring the dough together by pressing it together.
Press your cookie dough into an even layer into your prepared pan. Place the pan into the refrigerator to chill for 30-60 minutes.
Preheat your oven to 325°F while cookie dough chills.
When cookie dough has sufficiently chilled, generously sprinkle the top with coarse sugar and lightly with flaky sea salt.
Bake your shortbread for about 35 minutes. Check at 30 minutes. Remove from oven when shortbread is golden brown on edges. For a softer cookie, remove before it reaches a golden coloring on edges (about 30 min).
Remove shortbread from oven. Allow to cool in the pan for about 5 minutes then carefully remove to a cutting board. Cut the cookies while warm into bars.
Allow cookies to cool, then enjoy! Shortbread will firm up while it cools. Store in an airtight container.
