Preheat the oven to 350°F (175°C).

In a mixing bowl, combine the flour, granulated sugar, baking powder, and salt.

Add the softened butter, egg, vanilla extract, orange zest, and lemon zest to the dry ingredients and mix until well combined.

Drop spoonfuls of dough onto a baking sheet lined with parchment paper.

Bake for 10 minutes or until lightly golden.

In another bowl, whisk together the powdered sugar, fresh orange juice, fresh lemon juice, and orange zest until smooth.

Drizzle the glaze over the cooled cookies.