Preheat oven to 350°F (175°C). Line baking sheet with parchment paper.
Cream butter and sugar until light and fluffy. Beat in maple syrup and egg.
In another bowl, whisk flour, baking powder, and salt. Gradually add to wet mixture.
Scoop tablespoon-sized balls, place on baking sheet, and flatten slightly.
Bake for 10–12 minutes until edges are golden. Cool completely.
Mix powdered sugar and maple syrup for icing. Add milk to desired consistency.
Drizzle icing over cooled cookies. Let set before serving.