Preheat your oven to 350°F and line baking sheets with parchment paper.
In a large mixing bowl, cream together the softened butter and sugar until light and fluffy.
Add the egg and vanilla extract and mix until combined.
Add the salt, baking powder, and flour. Mix until the dough begins to come together.
Add the milk and continue mixing until fully combined.
Using a cookie scoop, portion about 1 tablespoon of dough onto the prepared baking sheets.
Bake for 10–12 minutes, or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire cooling rack.