Whisk the flour, baking powder, and salt together in a medium bowl. Set aside.
In a large bowl using a hand mixer or a stand mixer fitted with a paddle attachment, beat the butter and sugar together on high speed until completely smooth and creamy, about 2 minutes. Add the egg and vanilla extract and beat on high speed until combined, about 1 minute. Scrape down the sides and up the bottom of the bowl and beat again as needed to combine.
Add the dry ingredients to the wet ingredients and mix on low until combined. Dough will be relatively soft. If the dough seems too soft and sticky for rolling, add 1 more Tablespoon of flour.
Divide the dough into 2 equal parts. Cover with plastic wrap or aluminum foil, then refrigerate for at least 1-2 hours and up to 2 days.
Once chilled, preheat oven to 350°F (177°C). Line 2-3 large baking sheets with parchment paper or silicone baking mats.
With a lightly floured rolling pin, roll the dough out to about 1/4-inch thickness. Use more flour if the dough seems too sticky. The rolled-out dough can be any shape, as long as it is evenly 1/4-inch thick. Using a cookie cutter, cut the dough into shapes. Re-roll the remaining dough and continue cutting until all is used.
Arrange cookies on baking sheets 3 inches apart. Bake for 11-12 minutes or until lightly browned around the edges. If your oven has hot spots, rotate the baking sheet halfway through bake time. Allow cookies to cool on the baking sheet for 5 minutes then transfer to a wire rack to cool completely before decorating.