Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, beat the softened butter and granulated sugar together using an electric mixer or whisk until creamy and well combined.
Add the egg and vanilla extract to the butter-sugar mixture. Mix until fully incorporated.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing thoroughly until a dough forms.
If using, roll out the dough to about ¼ inch thickness on a floured surface and cut out desired shapes with a cookie cutter.
Place the cookies on the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 8-10 minutes, or until the edges are lightly golden. The centers may appear soft but will firm up as they cool.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
Decorate with sprinkles or icing if desired once they are cool.