In a large bowl, whisk together the flour, baking soda, and salt. Set aside.

Using an electric mixer, cream the butter and sugar until light and fluffy. Beat in the egg and vanilla until combined.

Add the dry ingredients and mix on low speed for several seconds. Stop mixer to scrape the bowl, then turn the mixer to high speed and beat until the batter is incorporated, about 1 minute.

Divide dough into two equal portions. Place each dough piece in plastic wrap. Wrap the dough pieces and flatten into disks. Refrigerate the wrapped disks for about 1 hour (or up to 3 days).

Preheat oven to 350° F.

Remove the first portion of dough and place on the counter. Unwrap the dough. Sprinkle powdered sugar on the bottom and top of dough. Place another sheet of plastic wrap on top of the dough. roll out the dough between the 2 sheets of plastic wrap.

Roll out first disk ¼ inch thick.

Cut into shapes and place on parchment-lined baking sheets; refrigerate until firm.

If using sprinkles, sprinkle them on before baking. Place at least 1-inch apart on greased baking sheet

Bake for about 10-12 minutes, rotating baking sheet halfway through baking time. Cookies should begin to turn golden brown around the edges. Repeat process with the other disk.

Let the cookies cool down completely on a wire rack. If you didn't decorate with sprinkles before baking, you could ice the cookies and add sprinkles.

Store cookies in an airtight container at room temperature for up to 1 week.