In a large bowl, whisk together the flour, baking powder and salt and set aside.
In a stand mixer using the paddle attachment or a hand mixer, cream the butter and sugar together. About 2-3 minutes on medium speed until it is fluffy looking.
Reduce speed to low and add in egg and vanilla extract, mixing until incorporated, stopping to scrape down sides of bowl as needed. Add flour mixture slowly, incorporating on low speed until combined and no flour pockets remain.
On a lightly floured surface, roll dough into a flatted ball/disc shape, cover well in plastic wrap and chill for 1 hour or up to overnight in the fridge. You can also freeze the dough, or a portion of the dough, at this point if saving for future.
Once ready to bake, remove dough from fridge or freezer and let come to just below room temperature. Usually about 20-30 minutes. Dough should be pliable but cool to the touch. Pre-heat oven to 350° and prepare a baking sheet with parchment paper or a silicone baking mat.
Working in batches to keep dough chilled, roll out dough on a floured surface to 1/4 inch thick. Use cookie cutters with edges dusted with flour to get desired shape. *the flour keeps the dough from sticking to the cutters to get clean sides. If dough becomes too warm, place dough shapes into the fridge to chill for 20 minutes. You can leave them right on the baking sheet. Chilled dough spreads less when baking than warm dough thus helping cookies to hold their shape.
Bake cookies for 10-11 minutes, rotating baking sheet once about halfway through. Do not let cookie edges get brown. These cookies should be uniform in color. If edges begin to brown, remove cookies from oven.
Let cookies cool for 5 minutes on baking sheet then move them to a wire rack to cool completely before decorating.