Preheat the oven to 350°.
Grease or spray the cookie sheets or use parchment paper.
With a mixer on medium speed, cream the butter and sugar until fluffy.
Beat in the egg and vanilla extract.
In a small bowl, mix the flour, baking powder, and salt together, then add to the creamed mixture and beat on low speed until a dough forms. (For this recipe, I often just add the dry ingredients right into the bowl and mix it well. )
On a lightly floured board, roll the dough to ¼-inch thickness. Start rolling with a small piece of dough, rather than roll the entire ball of dough at once.
Use cookie cutters to cut shapes. Use a thin metal spatula to transfer the shapes to the prepared cookie sheets. Place the cookies about an inch apart. (Decorate with sprinkles if you choose to add them before baking.)
Bake at 350° for 6 – 8 minutes or until the bottoms are just a light golden brown. Keep checking the cookies, since they are sensitive to the rack positioning. Every oven is different.
Immediately remove the cookies from the cookie sheets and place them on a wire rack to cool.
You can choose to spread icing on the cooled cookies and decorate with sprinkles or leave them plain.
These cookies last a few weeks when stored in a tin container.