In a medium bowl, whisk together the flour, baking powder, and salt until evenly combined.
In a large bowl, beat the softened butter and sugar until pale and fluffy.
Mix in the eggs one at a time, then add the vanilla extract and milk.
Add the dry ingredients gradually, mixing until a dough forms.
Divide the dough in half, shape each portion into a disk, and wrap tightly. Chill for 2 hours.
Roll the dough on a lightly floured surface to about 1/4-inch thickness. Cut into shapes with cookie cutters.
Place the cookies on parchment-lined baking sheets, leaving about 1 inch between each one. Chill the cut cookies for 5 to 10 minutes if the dough feels warm.
Bake at 375°F until the edges are lightly golden, usually 10 to 12 minutes.
Let the cookies cool on the pan for a few minutes, then transfer them to a wire rack.
Once completely cool, decorate as desired or enjoy them plain.