Remove butter from refrigerator and let stand at room temperature for approximately thirty minutes until softened. Place softened butter and granulated sugar in large mixing bowl.

Beat butter and sugar together using electric mixer on medium speed for two to three minutes until mixture becomes light, fluffy, and pale in color.

Add egg and vanilla extract to butter mixture, then continue beating for another minute until completely incorporated and smooth.

Add all-purpose flour to wet ingredients in two separate additions, mixing on low speed after each addition just until flour disappears, being careful not to overmix.

Cover mixing bowl with plastic wrap and refrigerate dough for minimum thirty minutes and up to two hours.

Preheat oven to 350°F and line two large baking sheets with parchment paper.

Roll chilled dough into balls approximately one inch in diameter, placing on prepared baking sheets with two inches spacing between each cookie.

Use fork to press crosshatch pattern into each dough ball, pressing firmly in one direction then rotating ninety degrees and pressing again to flatten cookies to approximately quarter inch thickness.

Sprinkle small pinch of coarse sea salt flakes over top of each cookie.

Bake for twelve to fifteen minutes until edges turn light golden brown while centers remain pale, rotating sheets halfway through.

Remove from oven and cool on sheets for five minutes, then transfer to wire cooling rack to cool completely.