Note: I recommend a stand mixer for this recipe, if you have one. If not, a hand mixer will work just fine.
Cream butter and sugar until light and fluffy- about 2 minutes, scraping the sides of the bowl occasionally. Add in egg and extract and mix to incorporate.
In a separate bowl combine flour, baking powder and salt. Tip: Don't use your measuring cup to scoop up the flour. Either weight it, or use a regular sized spoon and lightly spoon the flour into the cup and then level it off with a knife.
Slowly add the flour mixture to the butter mixture and mix until completely combined. Your dough may at first look crumbly, but keep mixing and it will quickly turn into a soft cohesive dough.
Refrigerate for at least one hour, OR use my method of pre-rolling as explained below.
Preheat oven to 350 F and line baking sheets with parchment paper.
Roll chilled dough and cut into shapes.
Bake for 8-12 minutes depending on the thickness of your cookies. Baking time is a personal preference. Watch for the edges and tops to be set. If you like your cookies crisp on the edges, roll them thinner and bake until just golden brown on the edges. If you want thick, soft cookies, remove from oven when cookies are puffed and set, but no browning is visible.