Preheat your oven to 325°F and line a 9x13 inch baking pan with parchment paper.

In a bowl of an electric mixer, combine the cold unsalted butter, powdered sugar, and vanilla extract. Beat until creamy, scraping down the bowl as needed.

With the mixer off, slowly add the all-purpose flour bit by bit. Mix until a soft dough forms.

If using, add the sprinkles and beat again to incorporate fully.

Shape the dough into a ball, then press it evenly into the prepared baking pan.

Chill the dough in the fridge for about an hour.

Once chilled, lift the dough out of the pan using the parchment paper and cut it into bite-sized squares.

Arrange the squares on an ungreased cookie sheet, leaving about an inch between them.

Bake for 10-12 minutes, keeping an eye on them—remove as soon as the bottoms start to brown.

Enjoy! Let them cool before diving in.