Preheat oven to 350F (175C) and line a baking sheet with parchment paper. Set aside.
Combine butter and sugar in a mixing bowl and use an electric mixer to beat together until creamy and well-combined.
½ cup unsalted butter, ⅔ cup granulated sugar
Add egg and vanilla extract and stir on medium/low speed until completely combined.
1 large egg, 4 teaspoons vanilla extract
In a separate bowl, whisk together flour, baking powder and salt.
1 ½ cups all-purpose flour, ¾ teaspoons baking powder, ½ teaspoon salt
Add about half of the flour mixture to the butter mixture and stir on low-speed to combine.
Add milk and stir again on low speed until combined.
1 Tablespoon milk
Finally, add remaining flour mixture and stir until combined.
Scoop dough into two-teaspoon sized scoops and drop onto prepared baking sheet, spacing cookies at least 2” (5cm) apart. Lightly flatten with damp fingertips.
Bake on 350F (175C) for 12-14 minutes or until cookies are light golden brown around the edges.
Allow to cool for 5-10 minutes on baking sheet then transfer to cooling rack to cool completely. Enjoy!